One year ago, Matt bought 100 shares of ABC Corp. stock for $5,619 including commission. He is about to sell the ABG stock for $6,528 net of commissions. When he made the purchase the S\&P 500 index was at 907 ; now it is 1070 . The beta of ACE stock is 0.98, and the market's risk-free rate is 4.0%. No dividends were paid. a. Evaluate the role of portfolio revision in the process of managing a portfolio