There is a family of six persons P, Q, R, S, T and U. Their professions are engineer, doctor, teacher, salesman, manager and lawyer.
I. There are two married couples in the family.
II. The manager is the grandfather of U, who is an engineer.
III. R, the salesman, is married to the lady teacher.
IV. Q is the mother of U and T.
V. The doctor, S is married to the manager.
Who are the two married couples in the family?