When adding 10,000 shares of stock JMR to the market portfolio M, an analyst knows that the only correct investment concept is: Oa. JMR's contribution to M's risk premium is the weight of JMR times its expected return the contribution of JMR to the variance of M can be measured by the covariance between O b. JMR and M divided by M's variance the reward to risk ratio for investing in JMR will be JMR's expected return divided by the covariance between JMR and M C. the reward to risk ratio for investing in JMR will be JMR's expected return divided by the d. correlation between JMR and M