Ava and a friend decide they are going to go to the fireworks on July 4th and steal as many phones as they can from spectators as they take photographs of the fireworks in the dark. They successfully take 2 or 3 without the somewhat inebriated individuals putting up much of a fight. During her final attempt to take a phone the victim starts to put up a fight and they each begin throwing punches. The friend finds a rock nearby and throws it at the head of a victim, leaving her unconscious and in a coma. If the victim dies, although Ava did not throw the rock, under what doctrine may she be held accountable?
a. principal liability
b. accessory after the fact
c. natural and probable consequences
d. derivative liability

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.