When an Investor Adds International Stocks to Her U

When an investor adds international stocks to her U.S.stock portfolio

A) it will raise her risk relative to the risk she would face just holding U.S.stocks.
B) she can reduce the risk of her portfolio.
C) she will increase her expected return, but must also take on more risk.
D) it will have no impact on either the risk or the return of her portfolio.
E) she needs to seek professional management because she doesn't have access to international investments on her own.