Question

15. This is the cause
the problem.
( Choose the correct preposition )
(A) on
(B) of
(C) off
(D) by
16. He gave
..... smoking.​

Answer 1

Answer:

I think maybe it is the preposition of

Answer 2

15) of

16) you haven't gave the options but I think the answer is 'up'

Hope that helps you