Which group has the smaller standard deviation? Select one: O a. Group A: 1,2,3, 10,20,25, 30,40. O b. Group B: 1,5, 10, 15,20,25, 30. O c. Group C: 20,21,22,23,24,25,26. O d. Group D: 20,40,50,60,80, 100, 110. In a normal distribution with a mean of 90 and a standard deviation of 10, which of the following scores lie within +/- one standard deviation from the mean? Select one: O a. 10 - 100. O b. 10 - 90. O c. 80 - 100. O d. 70 -110