The correct answer is: B. market risk
Market risk is the risk that a security’s price will fluctuate due to factors that affect the entire market, such as changes in interest rates, inflation, or economic conditions. This type of risk cannot be eliminated by diversification, as all stocks are affected by market forces.
Diversifiable risk, on the other hand, is the risk that is specific to a particular stock or industry. This type of risk can be reduced by diversification, as investing in a variety of stocks will help to offset the risk of any one stock declining in value.
Stock risk is the overall risk of a stock, which includes both market risk and diversifiable risk.
Portfolio risk is the risk of a portfolio of stocks, which is a combination of the market risk and diversifiable risk of the stocks in the portfolio.