With no explanation, chose the best option from "A", "B", "C" or "D". The second (categorical) classification traditionally “comprises cases in which the Court implements the proportionality standard by certain categorical restrictions on the death penalty,” but was recently expanded by the Supreme Court to include term-of-years sentences in narrow instances. See id. Walker asserts that his sentence violates the Eighth Amendment both categorically and as-applied. A. Walker argues that his 180-month sentence categorically violates the Eighth Amendment under Graham. However, this court has concluded that Graham does not apply in cases where the defendant receives a sentence that is “less severe” than a life sentence. See United States v. Jones, 476 Fed.Appx. 651, 652 (6th Cir.2012) (unpublished); United States v. Moore, 643 F.3d 451, 457 (6th Cir.2011) (<HOLDING>). Further, this circuit’s holdings emphasize

A: holding that mandatory life imprisonment without parole for those under the age of eighteen at the time of their crimes violates eighth amendment
B: recognizing that njeither graham nor miller explicitly  apply to the functional equivalent of life without parole ie de facto life sentences
C: holding that sentences imposing mandatory life imprisonment without the possibility of parole on individuals who committed their crimes when under the age of 18 violates the eighth amendment to the united states constitution
D: holding sentences of life without parole unique in their severity
D.