According to Cronin, which of the following is historically true of success in ending terrorist groups?

a. Capturing its leader has had a higher success rate than killing its leader.
b. Capturing its leader is an effective guarantor of the end of the terrorist group, though killing the leader is less effective.
c. To date, the capture or killing of a terrorist group leader has never resulted in the end of operations or the existence of that group.
d. The killing of a terrorist leader has historically shown more success in ending a terrorist group than the capture and imprisonment of a leader.
e. As long as a captured leader is not publicly killed, the nature of the imprisonment has little to no effect on the continued operation of that terrorist group.

Answer: b