Which statement is TRUE?

A. Managers should under no conditions take actions that increase their firm's risk relative to the market, regardless of how much those actions would increase the firm's expected rate of return

B. An individual stock's diversifiable risk, which is by its beta, can be lowered by adding more stocks to the portfolio in which the stock is held

C. If investors become less averse to risk, the slope of the Security Market Line (SML) will increase

D. According to the Capital Asset Pricing Model, investors are primarily concerned with portfolio risk, not the risks of individual stocks held in isolation. Thus, the relevant risk of a stock is the stock's contribution to the riskiness of a well-diversified portfolio.