The diners in the restaurant were enjoying a leisurely lunch. when the waiter slipped on the puddle of water. the salmon salad flew off the plate and straight into the actor's lap. rather than putting up a big fuss, the actor simply laughed off the accident. when the actor had cleaned up and eaten his lunch, he still left the horrified waiter a really big tip.

which of these is a sentence fragment?

a) the actor simply laughed off the accident.
b) when the waiter slipped on the puddle of water.
c) he still left the horrified waiter a really big tip.
d) the diners in the restaurant were enjoying a leisurely lunch.