Correct answer is (a) AB = PQ
Explanation: ABC \(\leftrightarrow\) PQR means triangles ABC and PQR are congruent to each other and if they are congruent to each other, AB = PQ, BC = QR and AC = PR.
Similarly ∠A = ∠P, ∠B = ∠Q and ∠C = ∠R.
And for vertices, A = P, B = Q and C = R.