The covariance is: O A. How much two random variables change together and is the arithmetic mean of the product of deviations of the values from their mean O B. None of the above O C. Correlation scaled by the standard deviations D. How much two random variables change together and is the geometric mean of the product of deviations of the values from their mean O E. How much two random variables change together and is the median of the product of deviations of the values from their mean