Let Xn = {1, 2, 3, ..., n} and let a subset A of Xn be chosen so that every pair of elements of A differ by at least 3. (For example, if n = 5, A can be ∅, {2} or {1,5} among others). When n = 10, let the probability that 1 ∈ A be p and let the probability that 2 ∈ A be q. Then -
(A) p > q and p – q = 1/6
(B) p < q and q – p = 1/6
(C) p > q and p – q = 1/10
(D) p < q and q – p = 1/10