Explanation:

- Principal (P): Rs 12,000.

- Rate of Interest (R): 10% per annum.

- Time (T): 3 months or 0.25 years.

- Compounding Frequency: Quarterly.

- Interest Formula (Compounded Quarterly): A = P (1 + (R/4)/100)^(4*T)

- A: Amount after time T.

- Calculation Steps:

- Convert annual interest rate to quarterly: R/4 = 10/4 = 2.5%.

- Calculate A = 12,000 * (1 + 0.025)^1 (since 3 months = 1 quarter).

- A = 12,000 * 1.025 = Rs 12,300.

- Interest Payable (I): A - P = Rs 12,300 - Rs 12,000 = Rs 300.

Correct Option: Option 3 - Rs 300