5.对债券现金流的贴现的函数以下那种写法是正确的
A.A cfs <- 100 * (rep(couponRate/frequency, n) + c(rep(0, n ),1))
B.B cfs <- 100 * (rep(couponRate/frequency, n-1) + c(rep(0, n - 1),1))
C.C cfs <- 100 * (rep(couponRate/frequency, n) + c(rep(0, n - 1))
D.D cfs <- 100 * (rep(couponRate/frequency, n) + c(rep(0, n - 1),1))