Choice "B" is correct. The primary disadvantage of using return on investment (ROI) rather than residual income (RI) to evaluate the performance of investment center managers is that ROI may lead to rejecting projects that yield positive cash flows. Profitable investment center managers might be reluctant to invest in projects that might lower their ROI (especially if their bonuses are based only on their investment center's ROI), even though those projects might generate positive cash flows for the company as a whole. This characteristic is often known as the "disincentive to invest."
Choice "a" is incorrect. The primary disadvantage of using return on investment (ROI) rather than residual income (RI) to evaluate the performance of investment center managers is that ROI may lead to rejecting projects that yield positive cash flows, not that ROI is a percentage and RI is a dollar amount. The fact that one is a percentage and one is a dollar amount might make them a little harder to interpret, but this interpretation difficulty would certainly not seem to be the "primary" disadvantage.
Choice "d" is incorrect. The primary disadvantage of using return on investment (ROI) rather than residual income (RI) to evaluate the performance of investment center managers is that ROI may lead to rejecting projects that yield positive cash flows, not that ROI does not necessarily reflect the cost of capital.
Choice "c" is incorrect. The primary disadvantage of using return on investment (ROI) rather than residual income (RI) to evaluate the performance of investment center managers is that ROI may lead to rejecting projects that yield positive cash flows, not that ROI does not reflect all economic gains.