Assertion (A): If 2 cos 3A = 1, A = 20°. Reason (R): cos 3A = 1/2 ⇒ 3A = 60° ⇒ A = 20° 1. A is true, R is false. 2. A is false, R is true. 3. Both A and R are true. 4. Both A and R are false.