Answer:
D.
Step-by-step explanation:
Derivative Liability can be defined as a liability faced by accomplices of main perpetrator. It is an accountability that's held by aider of principal criminal under the law.
In the given case, main perpetrator is Ava's friend who threw rock at the head of the victim. But Ava will be held accountable for this crime for being an accomplice of her friend. So, in the given case, Ava will be held liable under the doctrine of derivative liability.
Therefore, the correct answer is option D.