Interest on capital is computed using the formula: \[ \text{Interest on Capital} = \text{Capital Amount} \times \text{Rate of Interest}. \] Given Vivek's capital of ₹3,80,000 and an annual interest rate of 15%, the interest is calculated as follows: \[ \text{Interest on Capital} = ₹3,80,000 \times 15% = ₹57,000. \] Therefore, the correct option is (C).