Detailed Answer
Answer (D) is correct. The BEP in sales dollars is equal to total fixed costs divided by the CMR, and the CMR equals unit contribution margin divided by unit price. Equal percentage changes in the CMR numerator and denominator leave the overall ratio unaffected.
Algebraically, this can be shown as follows: If CM ÷ Price = CMR, then (1.1 × CM) ÷ (1.1 × Price) = CMR. With CMR unchanged, the ratio of fixed costs to CMR is unchanged.