Hi I need help answer the following question

Which of the following statements is true? source of systematic risk is the change in the interest rate by the Federal Reserve Bank. Your portfolio of 20 stocks in the same industry is well diversified Most of the portfolio's systematic risk is eliminated after 30 randomly chosen stocks are included in the portfolio. If you have two stocks that always move in the same direction in your portfolio, you can still achieve diversification effect. Labor strike for a company is called a systematic risk