Ibadan Solar Plc is computing its Weighted Average Cost of Capital (WACC). The company has the following market-value capital structure: Equity ₦600,000,000 (cost of equity 20%), 12% Bonds ₦400,000,000 (market value ₦400,000,000). The effective CITA tax rate is 30%. What is the WACC?

Total capital = ₦600m + ₦400m = ₦1,000m. Weight of equity = 0.60; weight of debt = 0.40. After-tax cost of debt = 12% × (1 − 0.30) = 8.4%. WACC = (0.60 × 20%) + (0.40 × 8.4%) = 12.00% + 3.36% = 15.36%. Option A ignores the tax shield on debt, Option C incorrectly applies the tax rate to the equity component, and Option D uses the pre-tax cost of debt.