Jessica signed up to be on a new reality television program, "Scareshow," where contestants were exposed to their fears for the chance to win prizes. When Jessica was on the set, the producers filled her trailer with dozens of snakes. Jessica was so frightened that she became physically ill, and sued the Scareshow producers for negligent infliction of emotional distress. Which one of the following defenses should the producers use to bar Jessica's recovery?
A. Sovereign immunity
B. Assumption of risk
C. Release of liability
D. Comparative negligence