Final answer:
The efficient frontier represents the set of portfolios that maximize return for each level of risk according to CAPM.
Step-by-step explanation:
The efficient frontier is a curve that represents the optimal portfolio combinations in terms of risk and return. It shows the trade-off between returns and risks for different asset allocations. Portfolios along the efficient frontier offer the highest possible returns for a given level of risk, or the lowest possible risk for a given level of return.
Investors can use the efficient frontier to identify the optimal combination of assets that align with their risk tolerance and desired return.