Which of the following terms is used to describe a measure of the price volatility...

Beta measures how sensitive a security’s returns are to movements in a broader market index (often described as the security’s volatility relative to the market). That makes choice A correct. Conceptually, beta estimates the degree to which a stock tends to move when the overall market moves. A beta of 1.0 suggests the security tends to move in line with the market. A beta greater than 1.0 indicates the security has historically been more volatile than the market (tending to rise more in up markets and fall more in down markets). A beta less than 1.0 indicates lower relative volatility. A negative beta (rare) indicates the security tends to move opposite the market.

Alpha, in contrast (choice B), is typically discussed as a measure of risk-adjusted excess return versus a benchmark—how much a manager or security outperformed/underperformed after accounting for market risk. The Sharpe ratio (choice C) measures risk-adjusted return using total volatility (standard deviation) and compares return above a risk-free rate per unit of risk; it is not a correlation-to-market measure. The P/E ratio (choice D) is a valuation metric (price per share divided by earnings per share) and does not measure volatility or correlation.

On the SIE, beta is most commonly tested as a systematic (market) risk concept. It relates to how much of a security’s risk is tied to broad market movements versus diversifiable company-specific factors. Understanding beta helps in portfolio construction and in explaining why some stocks are considered more aggressive or more defensive relative to market swings.