Please show full working with formulas used

(a) ) Explain how can a portfolio's risk be reduced through diversification? Is there any limit on the benefits of diversification? Explain. (b) ABC has a standard deviation of 42 percent per year and a beta of 0.2 while XYZ has a standard deviation of 25 percent and a beta of 0.8. Which stock is a safer investment for a diversified investor? Explain. (c) During the years from 2016 to 2020, the return of Ace Ltd and the S&P 500 are as follows: 2016 2017 2018 2019 2020 Ace Ltd 0.25 0.11 0.03 0.17 0.1 S&P 500 0.22 0.15 0.06 0.15 0.14 Calculate the average return and standard deviation of Ace Ltd and the S&P 500. Which one is a better investment