4. About the CAPM and relevant investment implications, correct statements are:( ) A Passive strategy should be all investor's choice; B Portfolio will contain assets having alpha values; C Investors will hold the market portfolio; D Beta value determines security's excess return against market; E CAPM can also be used in other fields except portfolio building. 5. Through diversifying, investors can reduce portfolio volatility caused by ( ). A Systematic risk; B Nonsystematic risk; C Firm-specific risk; D Risk of negative company news ; E Business cycle