Which statement is correct? The collection of all portfolios that minimize variance for varying levels of expected return is called the efficient frontier. The mean-variance frontier is the top-half of the efficient frontier. The part of efficient frontier with the highest expected return for a given level of variance is called the meanvariance frontier. The collection of all portfolios out of risky assets that minimize variance for varying levels of expected return is shaped like a hyperbola. The correlation of returns between securities A and B is -1 . The standard deviation of returns for A is 15% and for B is 35%. What is the weight that we should choose for A if we want to make the standard deviation of a portfolio consisting of A and B zero? \begin{tabular}{l} \hline 0.35 \\ \hline 0.15 \\ \hline 0.30 \\ \hline 0.70 \end{tabular}