在光滑的黑板上写字，不能使每一个学生都看清上面的字，因为[ ]

A．没有完全形成漫反射

B．字发生漫反射的光太弱

C．光滑黑板发生镜面反射的光太强

D．光滑黑板发生镜面反射，字发生漫反射，镜面反射的光比漫反射的光强

Compared with the net present value (NPV) method, the internal rate of return (IRR) method of evaluating investment projects:()

A. is the preferred method for evaluating mutually exclusive projects.

B. is not sensitive to the pattern or timing of the cash flows from the period.

C. assumes that all cash flows from the project will be reinvested at the computed IRR.