The probability of the complement of an event is ___ less than the probably of the event itself.

a. never

b. not enough information to answer this question

c. always

d. sometimes

The probability of the complement of an event is d) sometimes less than the probably of the event itself.

Your complement c=1-p

If you think of a dice you could have the probability to "get the number 1" = 1/6, so its complement would be 5/6 which is clearly more

if your event is instead "get a number from 1 to 6" then your probability would be 1=100% and the complement 0 which is less.