Which one of the following has a terminating decimal expansion?

If a rational number (q≠0) can be expressed in the form , where p ∈ Z, and m,n ∈ W, then the rational number will have a terminating decimal expansion.

Otherwise, the rational number will have a non-terminating and recurring decimal

expansion.

Now, 32 = 2⁵ × 5⁰ Hence, it has terminating decimal expansion.Hence, option A is correct.

Option B is incorrect ∵ 9 = 3² and it cannot be expressed in the form 2^m × 5ⁿ.

Option C is incorrect ∵ 15 = 3 × 5 and it cannot be expressed in the form 2^m × 5ⁿ.

Option D is incorrect ∵ 12 = 3 × 2² and it cannot be expressed in the form 2^m × 5ⁿ.

Hence, only option A is correct.