The positive integers P, Q, R, S, and T increase in order of size such ... ...

The positive integers P, Q, R, S, and T increase in order of size such that the value of each successive integer is one more than the preceding integer and the value of T is 6. What is the value of R?
(A)    0
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Math - Problem Set Y: Sequences & Series