Alice and Bob are portfolio managers from two fund houses. They are both using modern portfolio theory, specifically mean-variance optimisation, to construct their portfolios. The following table shows the weightings of their portfolios: Manager risk-free asset Stock A Stock B Stock C Stock D Stock E Alice 10% 20% 25% 30% 5% 10% Bob 5% 20% 10% 30% 20% 15% Give three possible reasons why Alice and Bob result in different portfolios