3743: The letters L, M, N, O, P, Q, R, S and T in their order are substituted by nine integers 1 to 9 but not in that order, 4 is assigned to P. The difference between P and T is 5. The difference between N and T is 3. What is the integer assigned to N?
(a) 7
(b) 5
(c) 4
(d) 6