" 'As defined in the Rules of Court, an enhancement "means an additional term of imprisonment added to the base term." ' ( People v. Hernandez (1988) 46 Cal.3d 194, 207 249 Cal.Rptr. 850, 757 P.2d 1013, quoting Cal. Rules of Court, rule 405(c), and citing Cassou & Taugher, Determinate Sentencing in California: The New Numbers Game (1978) 9 Pacific L.J. 5, 22-24.)" ( People v. Wims, 10 Cal.4th 293, 304.) Penal Code Section 667.61 imposes an indeterminate life term when specified circumstances are found; it does not add to the base term. When specifically called upon to characterize section 667.61, the courts have declared that "the one strike law is a 'penalty provision' and not a true 'enhancement.' " (People v. Jones (1997) 58 Cal.App.4th 693, 709.) The California high court declared that section 667.61, "sets forth an alternative and harsher sentencing scheme for certain enumerated sex crimes perpetrated by force, including rape, foreign object penetration, sodomy, and oral copulation." (People v. Mancebo (2002) 27 Cal.4th 735, 741.) Upon a requisite finding, section 667.61 allows "an elevated term on each current count," rather than an enhancement predicated upon an addition to the base term. (People v. DeSimone, supra, 62 Cal.App.4th 693, 697.) Like the three strikes law, section 667.61 is not an enhancement, but instead defines the term for the crime itself. (See People v. Sipe (1995) 36 Cal.App.4th 468, 485; People v. Martin, supra, 32 Cal.App.4th 656, 667.) When a determinate sentencing statute authorizes three possible terms of imprisonment, "the choice of the appropriate term shall rest within the sound discretion of the court." ( 1170, subd. (b).) "The court shall select the term which, in the court's discretion, best serves the interests of justice." (Ibid.) In exercising that discretion, the sentencing court "may consider circumstances in aggravation or mitigation, and any other factor reasonably related to the sentencing decision." (Cal. Rules of Court, rule 4.420(b).) The relevant circumstances may be obtained from the record in the case, the probation report, statements from the victim of the crime and evidence introduced at the sentencing hearing. ( 1170, subd. (b); rule 4.420(b).) When imposing a sentence enhancement punishable by one of three terms, the court is also authorized, in its discretion, to "impose the term that best serves the interest of justice." ( 1170.1, subd. (d).) The existence of a single aggravating circumstance is legally sufficient to make the defendant eligible for imposition of the upper term. (People v. Black (2007) 41 Cal.4th 799, 816; People v. Osband (1996) 13 Cal.4th 622, 728; see People v. Quintanilla (2009) 170 Cal.App.4th 406, 413.) Moreover, the use of the same fact or facts to aggravate both a base term and the sentence on an enhancement is permissible. (People v. Chism (2014) 58 Cal.4th 1266, 1336; People v. Moberly (2009) 176 Cal.App.4th 1191, 1198.) Notwithstanding the trial court's broad discretion in crafting a sentence, generally reviewable only for abuse, "the court may not impose an upper term by using the fact of any enhancement upon which sentence is imposed under any provision of the law." ( 1170, subd. (b); see rule 4.420(c) "a fact charged and found as an enhancement may be used as a reason for imposing the upper term only if the court has discretion to strike the punishment for the enhancement and does so".) Similarly, a fact that is an element of the offense may not be used as a reason to impose the upper term. (Rule 4.420(d).) Although such dual use of facts to impose an upper term or an enhancement is improper, "'complaints about the manner in which the trial court exercises its sentencing discretion and articulates its supporting reasons cannot be raised for the first time on appeal.'" (People v. Boyce (2014) 59 Cal.4th 672, 730, quoting People v. Scott (1994) 9 Cal.4th 331, 356; accord, People v. McCullough (2013) 56 Cal.4th 589, 594-595.) "'Claims involving the trial court's failure to properly make or articulate its discretionary sentencing choices' are subject to forfeiture, including 'cases in which the stated reasons allegedly do not apply to the particular case, and cases in which the court purportedly erred because it double-counted a particular sentencing factor, misweighed the various factors, or failed to state any reasons or to give a sufficient number of valid reasons.'" (Boyce, at p. 731.)