Paul is studying for a test in biology. He is somewhat concerned about his ability to master the material and is trying to concentrate as much as he can

Sam, his brother, has interrupted his studies several times, causing Paul to become frustrated and angry. When Sam again enters Paul's room, Paul pushes Sam hard, and threatens to punch him. This situation illustrates ________.
A) the fighting instinct
B) thanatos
C) the catharsis hypothesis
D) hostile aggression
E) the frustration-aggression hypothesis

Answer: E