Correct option is A
GIVEN: Seven persons M, N, O, P, Q, R and S
Solution:
1) Only four persons sit between O and R.
CASE 1

CASE 2

2) Only two persons sit between N and M and M sits immediately above Q.
CASE – 1 is not possible in this condition So,
CASE 2:

3) O sits below M. N sits above M.
CASE 2

Hence, ‘Two’ persons are sitting between P and S.