Which of the following equations is INCORRECT?

A$.E[Rp]=E[iRi]$

B$.Rp=iRi$

C$.Rp=x1R1+x2R2+$dots$+xnRn$

D$.=\frac{\text{T}\text{o}\text{t}\text{a}\text{l}\text{v}\text{a}\text{l}\text{u}\text{e}of\text{p}\text{o}\text{r}\text{t}\text{f}\text{o}\text{l}\text{i}\text{o}}{\text{V}\text{a}\text{l}\text{u}\text{e}of\text{i}\text{n}\text{v}\text{e}\text{s}\text{t}\text{m}\text{e}\text{n}\text{t}i}$

Which of the following investments had the largest fluctuations in overall return over the past ninety $-$ six ye

A$.$ Corporate bonds

B$.$ SRP $500$

C$.$ Treasury Bils

D$.$ Small stocks