Tim Burns Fears for His Life from an Attacker

Tim Burns fears for his life from an attacker.Which rule must he follow in defending himself from his attacker?

A) Tim is obligated to first attempt to retreat from the attack even if he cannot ascertain any way to do so.
B) Tim must use only the degree of force necessary to stop his attacker.
C) Tim must wait until he has actually been physically assaulted before acting in self-defense.
D) Tim is obligated to render first aid to his attacker if the attacker is injured while committing the assault.