The risk-free rate, expected returns and standard deviations for four individual stocks are given below. The investor must develop a complete portfolio by combining the risk-free asset with one of the securities. To achieve the best CAL, the investor would choose ________.

Stock	Expected Return	Std dev
A	20%	10%
B	30%	16%
C	40%	20%
D	12%	5%
Risk free	5%