(i) If R = {(x,y) : x, y ∈ Z, x – y ∈ Z}, then the relation R is

(a) Reflexive but not transitive

(b) Reflexive but not symmetric

(c) Symmetric but not transitive

(d) An equivalence relation.

(ii) Let * be a binary operation on the set Q of rational numbers by a*b = 2a + b. Find 2 * (3 * 4) and (2 * 3) * 4.

(iii) Let ƒ : R → R, g : R → R be two one-one funçtions. Check whether gof is one-one or not.