The right use of alpha is to determine whether to add the portfolio of a candidate manager (say, of some mutual fund family) to your portfolio. The way you obtain the right alpha is to regress...

A. Historical (excess) returns of the candidate manager onto historical (excess) returns of a benchmark portfolio with the same industry composition as the candidate manager's portfolio

B. Historical (excess) returns of the candidate manager onto historical (excess) returns of your portfolio

C. Historical (excess) returns of the candidate manager onto historical (excess) returns of a benchmark portfolio with the same risk characteristics as the candidate manager's portfolio

D. Historical (excess) returns of the candidate manager onto historical (excess) returns of a market-wide benchmark portfolio