If the correlation was higher, diversification would help less, so the risk would be higher. Therefore, the efficient frontier would not bend as far toward the west (a risk of 0). An easy way to check this is to rearrange the returns so that they correlate more positively, as you will do in the next question. If the correlation was lower, diversification would help more, so the risk would be lower. Therefore, the efficient frontier would bend closer toward the west (a risk of 0).