The systolic blood pressure readings (in mm Hg) for a group of ten college students are listed below. Use the range rule of thumb to estimate the standard deviation. Round results to the nearest tenth. 130 122 163 171 144 151 155 156 161 157 O A. 8.8 mm Hg O B. 10.3 mm Hg O C. 1213 mm Hg O D. 6.8 mm Hg