Which of the following statements is correct?

A. The standard deviation of the portfolio is more than the weighted average of the standard deviations of the assets in the portfolio because the coefficients of correlation between securities are usually less than 1.

B. The portfolio standard deviation equals the weighted average of the component-asset standard deviations only in the special case that all assets are perfectly positively correlated.

C. The standard deviation of the portfolio is always equal to the weighted average of the standard deviations of the assets in the portfolio.

D. As the formula for portfolio standard deviation shows, the portfolio standard deviation is no less than the weighted average of the component-asset standard deviations.