could you please do formula and not excel

a) Discuss the benefit of portfolio diversification. Explain how to achieve diversification benefit.

b) The standard deviation of a portfolio's return can be reduced to zero by holding all the securities in the market. True or false? Explain.

An investor buys 1 share of Zephyr Ltd at the price of $38 on January 1, 2020. The firm is not expected to pay any dividends. The investor believes that the share price on January 1, 2021 will be one of the three following values:

• $56, with a probability of 35%
• $42, with a probability of 55%
• $24, with a probability of 10%

c) Calculate the expected return for holding the share for a year.

d) Calculate the variance of return and standard deviation of return.

could you please do formula and not excel