The standard deviation of a portfolio of risky securities is

A) the square root of the weighted sum of the securities' variances.
B) the square root of the sum of the securities' variances.
C) the square root of the weighted sum of the securities' variances and covariances.
D) the square root of the sum of the securities' covariances.

Variances

The quantitative measure of the difference between actual and expected behavior, often used in finance to assess volatility of returns or tracking errors.

Covariances

An indicator of the extent to which two variables fluctuate in tandem.

Risky Securities

Financial instruments carrying a higher potential for loss, often offering greater potential returns to compensate for the increased risk.