He fell heavily (1)/ and this caused (2)/ him great pain. (3)/ No error (4)

Answer

3

Explanation

a great pain will replace great pain because -
if there is an Adj./an Adv.- Adj. Combination before the Noun, a/an (Indef. Art.) agree with the first sound in the adj./Adv. - Adj. combination.
Look at the examples given below:

Hence, him a great pain is the right usage.