The letters L, M, N, O, P, Q, R, S and T in their order are substituted by nine intergers 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 ?
Option:
A. 4
B. 5
C. 6
D. 7
