Comprehensive and Detailed In-Depth Explanation:
The Internal Rate of Return (IRR) is the discount rate that makes the net present value (NPV) of a project equal to zero. It is used to evaluate the profitability of investments.
Option A (Annual cost of capital) - While related, the IRR should be compared directly to the required rate of return (hurdle rate).
Option B (Annual interest rate) - Not always relevant, as the cost of borrowing may differ from the required return on investments.
Option D (Compare to NPV) - NPV is a different method of capital budgeting; while related, it is not used for direct comparison with IRR.
Since the IRR is accepted if it meets or exceeds the required rate of return, Option C is correct.
Reference: IIA Financial Management - Capital Budgeting Techniques

Reference: IIA Business Knowledge for Internal Auditing, Cybersecurity and IT Risks section.