Final answer:
The statement is true because the efficient frontier represents optimal portfolios and beta measures systematic risk, both key elements of Modern Portfolio Theory.
Step-by-step explanation:
The question pertains to Modern Portfolio Theory (MPT), which indeed considers both the efficient frontier and beta as significant components. The efficient frontier represents a set of portfolios that offer the highest expected return for a given level of risk. On the other hand, beta measures the volatility, or systematic risk, of a security or a portfolio in comparison to the market as a whole. The statement that 'Both the efficient frontier and beta are important aspects of MPT' is therefore true (A).