(a) "If you don't know the actual probability distributions of future asset returns you cannot apply the portfolio theory to real life markets. For this reason, portfolio theory has only conceptual value and is not useful in practice." Do you agree with this statement?

(b) "From the point of view of an investor with mean-variance preferences who constructs a portfolio with N risky assets and one riskless asset, the Tangency portfolio (T) will dominate all other possible portfolios consisting of N risky assets and one riskless asset because it achieves the highest possible Sharpe ratio." Do you agree with this statement?