Assertion (A): log 2 = a and log 3 = b

⇒ 1 + log 12 = 2a + b

Reason (R): 1 + log 12

= 1 + log 2 x 2 x 3

= 1 + 2log 2 + log 3

= 1 + 2a + b

1. A is true, but R is false.

2. A is false, but R is true.

3. Both A and R are true and R is the correct reason for A.

4. Both A and R are true and R is the incorrect reason for A.

If log₂ x = a and log₃ y = a, write 72^a in terms of x and y.