Which of the following statements are correct?

I. The variance is commonly used as a measure of volatility. II. The greater the variance, the greater the dispersion of actual returns. III. The higher the standard deviation, the less certain the rate of return in any one given year. IV. Lower standard deviation is usually associated with the higher expected return.

II, III, and IV only

I, II, III, and IV

I, III, and IV only

II and III only

I and III only