With no explanation, chose the best option from "A", "B", "C" or "D". be two levels lower. See U.S.S.G. § 2Dl.l(c)(4). We review a sentencing court’s drug-quantity calculations for clear error. United States v. Cintron-Echautegui, 604 F.3d 1, 6 (1st Cir.2010). Generally, “we must honor such findings ‘unless, on the whole of the record, we form a strong, unyielding belief that a mistake has been made.’ ” United States v. Platte, 577 F.3d 387, 392 (1st Cir.2009) (quoting Cumpiano v. Banco Santander Puerto Rico, 902 F.2d 148, 152 (1st Cir.1990)). “The calculation of drug quantities is not an exact science, and a sentencing court charged with that responsibility need not be precise to the point of pedantry. Rather, a sentencing court may make reasoned estimates based on historical data.” Id. See also United States v. Kinsella, 622 F.3d 75, 86 (1st Cir.2010) (<HOLDING>). Under this deferential standard, we see no

A: recognizing that a sentencing judge is not required to be a mathematician or to make findings with computerized certainty
B: recognizing that sentencing judges have the discretion to reject any sentencing guideline but no judge is required to do so
C: recognizing appellate courts must not make fact findings
D: holding that it is not an appellate courts function to make findings of fact
A.