Final answer:
The term for a graph that represents optimal portfolios and the trade-off between risk and return, according to modern portfolio theory, is Efficient frontier.
Step-by-step explanation:
The term for a graph that represents optimal portfolios and the trade-off between risk and return, according to modern portfolio theory, is Efficient frontier.
The efficient frontier is a curve that shows all the possible portfolios that can be constructed with a given set of assets, while maximizing expected return for a given level of risk or minimizing risk for a given level of expected return. It helps investors understand the relationship between risk and return and find the optimal portfolio that suits their investment goals.