Answer the questions based on the information given below. There are eight persons M, N, O, P, Q, R, S, and T in a family of three generations. No single person in the family is a parent. R is the son of M, who is the sister-in-law of P. N is the son of O, who is the grandfather of S, who is an unmarried female. Q is the daughter-in-law of N. The gender of T and P is different. How is S related to M?