The Ex Ante Real Interest Rate That Prevails at Time $\pi$

The ex ante real interest rate that prevails at time t equals:

A) i_t - E_t $\pi$ _t
B) i_t - E_t $\pi$ _{t + 1}
C) i_t - $\pi$ _t
D) i_t - $\pi$ _{t + 1}