Risk and Rate of Return Discussion Board

Due 5/30/19 12:00 pm pacific time. It is for a discussion board post. 

~250-300 words

An investor "A" has a well-diversified portfolio. What risk measure is the most relevant in this case, standard deviation or beta? Why? Explain!

If risk-free rate is 4% beta of stock ABC is 1.5, and expected return on the market is 8%, what is the required rate of return on stock ABC? Now, assume you expect to realize an annual return of 12% by holding ABC, should you buy it or not, why? Explain.