With no explanation, chose the best option from "A", "B", "C" or "D". quotation marks omitted). Substantive reasonableness pertains to “whether the length of the sentence is reasonable in light of the factors contained in 18 U.S.C. § 3553(a).” Id. “We apply a rebuttable presumption of reasonableness to a below-guideline sentence challenged by the defendant 'as unreasonably harsh.” United States v. Ray, 704 F.3d 1307, 1317 (10th Cir.2013) (internal quotation marks omitted). Benoit first contends his sentence is procedurally unreasonable, but he offers scant argument to support his contention. He mentions procedural error only when vaguely referencing a district court’s discretion to vary from the Guidelines due to a categorical policy disagreement. See, e.g., Spears v. United States, 555 U.S. 261, 264, 129 S.Ct. 840, 172 L.Ed.2d 596 (2009) (per curiam) (<HOLDING>). Benoit seems to suggest the district court

A: holding that district court did not err in determining that cocaine base was crack cocaine based on chemical analysis identifying cocaine base together with competent lay testimony bridging the evidentiary gap between cocaine base and crack cocaine and refusing to require showing of smokeability ie water solubility or melting point for purposes of establishing crack cocaine under the guidelines since smokeability distinguishes cocaine base from powder cocaine not from crack
B: recognizing district courts ability to vary from guidelines based on policy disagreement with sentencing range in cases involving child pornography
C: holding a district court has authority to vary from the crack cocaine guidelines based on a policy disagreement with them italics omitted
D: holding district courts are entitled to vary from the guidelines based on a policy disagreement with those guidelines
C.