Portfolio A has a beta of .2 and an expected return of 14%. Portfolio B has a beta of .4 and an expected return of 16%. The risk-free rate of return is 10%. If you manage a long-short equity fund and want to take advantage of an arbitrage opportunity, you should take a short position in portfolio ______ and a long position in portfolio

A; A

A; B <---- correct

B; A

B; B

Hello, I have the correct answer to this problem but i do not understand why. Would someone be able to explain please