Why Did the Supreme Court Declare the Death Penalty to Be

Why did the Supreme Court declare the death penalty to be unconstitutional, as administered?

A) because in capital trials, guilt and sentence were determined in one set of deliberations (instead of bifurcated proceedings)
B) because juries were given complete discretion to decide whether to impose the death penalty or a lesser punishment in capital cases
C) because prospective jurors were being excused simply because they were opposed to capital punishment
D) because to impose the death penalty, jury recommendations were required
All of the above