Until Very Recently, Youth Were Subject to Execution in the United

Until very recently, youth were subject to execution in the United States if they committed capital crimes. The U.S. Supreme Court ruled recently that

A) because the United Nations. Convention on the Rights of Children barred capital punishment or life imprisonment without possibility of parole for those under 18 at the time they committed their crime, in the United States youth who cmmited capital offenses could serve no more than 20 year terms
B) because the American Bar Association and other professional groups argued in an amicus brief that adolescence is not an excuse for crime youth who committed adult crimes should not escape punishment.
C) because the consensus in the United States had changed, those under age 18 at the time they committed their crime were less culpable because of their immaturity and it would violate the Eighth Amendment 's prohibition against cruel and unusual punishment to execute such a youth
D) it was irrelevant to American law that every other country in the world still executed youth