Eight girls - L, M, N, O, P, Q, R and S - were seated in two rows, one facing the north, the other facing the south. Each row had only four chairs. There is equal distance between adjacent persons. Each person in a row faces another person from the other row. Q and P were diagonally opposite to each other. M was opposite to P. R was to the immediate right of L. S was second to the right of M. N was at one of the extreme ends of the row. Who among the following girls was sitting opposite to O?