An individual stock's diversifiable risk, which is measured by its beta, can be lowered by adding more stocks to the portfolio in which the stock is held.

We are given the statement above. I think we are supposed to determine if the statement is true or false. If this is the case, then the answer is TRUE. The diversifiable risk can be lowered if there are more stocks added to the portfolio. The nature of the diversifiable risk is that the less the stocks in each portfolio, the greater the risk.