D是vasicek或CIR吗

问题如下：

An analyst is looking at various models used to incorporate drift into term structure models. The Ho-Lee Model:

选项：

A.Incorporates no-risk premium to the interest rate model allowing rates to vary according to their volatility. B.Incorporates drift as a premium to interest rates that remains constant over time. C.Allows for a risk premium to be applied to interest rates that changes over time. D.Incorporates drift into the model following the assumption that rates revert to the long-run equilibrium value.

解释：

Choice C is correct. The Ho-Lee model incorporates a premium to each rate change that can be different at each point in time.