Bobby voluntarily enrolls in a skydiving course at OpenSkies Pvt. Ltd., an adven

Bobby voluntarily enrolls in a skydiving course at OpenSkies Pvt. Ltd., an adventure firm. He signs a contract that relieves OpenSkies of liability. After receiving proper instruction, he jumps from an airplane. Unfortunately, Bobby is injured when he could not steer his parachute toward the target area while landing. He sues the parachute center for damages. But the court found that the contract protected OpenSkies from damages, as Bobby had voluntarily joined the course knowing all the risks involved. What kind of contractual provision protected OpenSkies from having to pay Bobby damages?
A) noncompete clause
B) exculpatory clause
C) duty of restitution
D) disaffirmance

This is for my business law class, anything will help