The March 2011 "triple disaster" refers to

a. North Korean missile tests that destroyed three Japanese fishing vessels.
b. a critical point in the conflict between Japan, Vietnam, and China over water rights.
c. a chemical spill, an industrial accident, and a bridge collapse that killed hundreds, all happening within weeks of one another.
d. an earthquake, a resulting tsunami, and a meltdown at a Japanese nuclear reactor.
e. three simultaneous attacks on the Japanese transportation system by a religious cult.

d