Correct option is D
Given:
A group of friends are playing a game sitting together facing north.
A group of friends are playing a game sitting together facing north.
Rehana is to the left of Arjun, who is seated exactly in front of Somil.
Arjun exchanges his position with Somil.

After Arjun exchanges his position with Somil, Rehana is now in North-West direction of Arjun.
Thus, correct option is (d).