Consider an investor who owns three assets: asset 1, asset 2, and asset 3 and invests equally in each of the three assets. If the beta of asset 1 is 1.2, the beta of asset 2 is 1.5 and the Beta of asset 3 is zero, then what is the beta of the investor's portfolio.
A) 0.90
B) 1.10
C) 1.25
D) 0.75