Gumbo Inc. has the following returns for 19921994: 7%,13%, and 10%. Use the following formulas to calculate the variance of the returns and the standard deviation of the returns: Variance (r~m)= expected value of (r~mrm)2 Standard deviation of r~m=variance(r~m) a. 124% and 11.1% b. 30% and 10% c. 6% and 2.45% d. 64% and 8%