Explanation:

- Sunil invests Rs. x in Scheme A.

- Scheme A offers 15% per annum for 2 years at Simple Interest.

- The interest from Scheme A is: \( \frac{15}{100} \times x \times 2 = 0.3x \).

- Sunil also invests Rs. (x + 500) in Scheme B.

- Scheme B offers 12% per annum for 2 years at Simple Interest.

- The interest from Scheme B is: \( \frac{12}{100} \times (x + 500) \times 2 = 0.24x + 120 \).

- The total interest from both schemes is Rs. 4224.

- Equation is: \( 0.3x + 0.24x + 120 = 4224 \)

- Solving it gives \( 0.54x + 120 = 4224 \).

- Therefore, \( 0.54x = 4104 \).

- This means \( x = 7600 \).

- Answer: Option 2 – 7600