Which of the following statements is CORRECT? A stock's beta is less relevant as a measure of risk to an investor with a welldiversified portfolio than to an investor who holds only that one stock. If an investor buys enough stocks, he or she can, through diversification, eliminate all of the diversifiable risk inherent in owning stocks. Therefore, if a portfolio contained all publicly traded stocks, it would be essentially riskless. Portfolio diversification reduces the variability of returns (as measured by the standard deviation) of each individual stock he? in a portfolio. A security's beta measures its non-diversifiable, or market, risk relative to that of an average stock