Let R be set of points inside a rectangle of sides a and b (a, b > 1) with two sides along the positive direction of x-axis and y-axis. Then

(A) R = {(x, y) : 0 ≤ x ≤ a, 0 ≤ y ≤ b}

(B) R = {(x, y) : 0 ≤ x < a, 0 ≤ y ≤ b}

(C) R = {(x, y) : 0 ≤ x ≤ a, 0 < y < b}

(D) R = {(x, y) : 0 < x < a, 0 < y < b}