L, M, N, O, P, Q, and R are sitting in a row facing east. O is sitting immediate right to N. Q sits at one of the ends of the row and P sits immediately adjacent to it on the right. L is sitting between M and N. Who is sitting at the right end of the row?

Given : L, M, N, O, P, Q, and R are sitting in a row facing east.

Explanation : 

1) Q sits at one of the ends of the row and P sits immediately adjacent to it on the right.

2) L is sitting between M and N.

3) O is sitting immediate right to N.

As position of N is not known yet therefore, therefore there are two possible position for O.

As After positioning L, M, N and O only one position is left which will be occupied by the only person left i.e R.

Here, according to the final arrangement R is sitting at the right end of the row.

Hence, "R" is the correct answer.