In Certainty-equivalent approach, adjusted cash flows are discounted at:?

<p style="text-align:justify;"><strong><span>(a) Accounting Rate of Return,</span></strong></p> <p style="text-align:justify;"><strong><span>(b) Internal Rate of Return,</span></strong></p> <p style="text-align:justify;"><strong><span>(c) Hurdle Rate,</span></strong></p> <p style="text-align:justify;"><strong><span>(d) Risk-free Rate</span></strong></p>