Convicted murderer of four family members, James Kahler, appealed his guilty verdict all the way to the U.S. Supreme Court, questioning whether:

a. prohibiting expert psychological testimony for a defendant suffering from psychosis was constitutional.
b. the state not having a mens rea defense is a violation of the constitution.
c. the state only allowing a mens rea defense violated the protection against cruel and unusual punishment.
d. None of the above.