问题如下：
Is it appropriate to use the expected return of the assets used to fund their spending needs when calculating the capitalized value of the core capital spending needs? Why or why not?
选项： 解释：
It is not appropriate to use the expected return of the assets used to fund spending needs to calculate the capitalized value of the core capital needs, because the risk of the spending needs is unrelated to the risk of the investment portfolio used to fund those needs.
Although the annual spending cash flows are not riskless, a risk-free rate should be used to calculate the present value of the cash flows as their uncertainty is unrelated to market risk factors that would be priced in a normal asset pricing model, making their beta equal to zero.
能解释一下吗？为什么用rf，不用expected return来计算core capital？
