Cytochrome c is released from an injured mitochondrion and binds to Apaf-1. Apaf1+cytochrome c binds to procaspase-9, which promotes the aggregation of procaspase-9 and activates caspase-9.

A) Cytochrome c inhibits apoptosis.
B) Apaf-1 has no role in caspase activation.
C) Procaspase-9 aggregation is independent of cytochrome c.
D) Caspase-9 activation involves the binding of Apaf-1 and cytochrome c.