Egg Laying in Fruit Flies Can Be Triggered (Induced) When

Egg laying in fruit flies can be triggered (induced) when males deposit their sperm in the spermathecae of the females. What is the selective advantage of induced egg laying for the male flies?

A) Because egg laying is induced upon mating, the males do not have to produce as much sperm.
B) More eggs can be fertilised at once when egg laying is induced.
C) Induced egg laying ensures that a male fly's sperm is used for fertilisation.
D) Mating takes less time, so less energy is expended by the males.