With no explanation, chose the best option from "A", "B", "C" or "D". to that extent. Reed, supra, at 17, 104 S.Ct. 2901. The holding in Cage represents a degree of novelty sufficient to constitute cause. As such, Mercer has established cause to avoid otherwise procedurally defaulting on his claim challenging the reasonable doubt instruction. Sufficient prejudice to establish federal habeas jurisdiction also exists. In particular, the Supreme Court has held that the Fifth Amendment requirement of proof beyond a reasonable doubt in criminal cases is so intertwined with the Sixth Amendment right to a jury verdict that a constitutionally deficient jury instruction cannot produce a guilty verdict comporting with due process but, rather, requires reversal of a conviction. Sullivan v. Louisiana, 508 U.S. 275, 277-80, 113 S.Ct. 2078, 124 L.Ed.2d 182 (1993) (<HOLDING>). It follows that a claimed Cage violation

A: holding a cage violation could never be held harmless error and thus not amenable to harmless error review but rather required outright reversal
B: holding exclusion was harmless error
C: recognizing that where the error involved defies analysis by harmless error standards or the data is insufficient to conduct a meaningful harmless error analysis then the error will not be proven harmless beyond a reasonable doubt
D: holding that when defendant properly objects to charge error reversal required unless error was harmless
A.