How many people sit between C and the person whose joining date is in April?

From the information given in the question, we can have the following table:
Eight people, viz A, B, C, D, E, F, G and H are sitting in a straight line facing North. Each of them has passed a recruitment exam and must join the office in different months, viz January, February, March, April, May, June, July and August but not necessarily in the same order.
From figure we can see that two people sit between C and the person whose joining date is in April .