Bystander Effects Occur When

Bystander effects occur when:

A) winning a contest increases the probability of winning future contests.
B) individuals change their fighting behavior if they are watched.
C) losing a contest decreases that probability of winning future contests.
D) bystanders actively interfere with the aggressive interactions between two conspecifics.
E) the observer of an interaction changes its assessment of the fighting abilities of those that it observed.