The Durbin Two-Stage Procedure estimates rho:
a. indirectly using the residuals from the OLS regression
b. indirectly using the residuals from the WLS regression
c. directly using Yt = rhoYt-1 + β1(1-rho) + β2X2 + rhoβ2X2,t-1 + ... + βkXk,t + rhoβkXk,t-1 + εt
d. directly using Yt = β1 + β2X2 + ... + βkXk,t + εt
e. none of the above
