Consider the below representation of a three-asset portfolio space with iso-expected return and iso-variance curves depicted as dashed lines. Note that each lettered dot corresponds to a portfolio. Note also that Asset 2 has the highest expected return, followed by Asset 3, with Asset 1 having the lowest expected return.

If investors are able to take arbitrary short positions, what point in the above graph represents the minimum variance portfolio?

If investors are able to take arbitrary short positions, what portfolios lie on the efficient frontier?

For an investor restricted by Non-Negativity constraints, what point in the above graph represents the minimum variance portfolio?

For an investor restricted by Non-Negativity constraints, identify two portfolios that investor would strictly prefer to portfolio C.