The Conviction of Ennis Cosby's Killer Was Aided by the DNA

The conviction of Ennis Cosby's killer was aided by the DNA analysis on a hair that was crucial evidence in the case.This hair:

A) Belonged to Cosby and was found in the suspect's car.
B) Belonged to the killer and was found in his cap with which he had wrapped the murder weapon before discarding it.
C) Belonged to Cosby and was found clinging to the murderer's jacket.
D) Belonged to the killer and was found on the body of the victim.