For a group experiment, your science class measured the fine particulate concentrations in the air at random places around campus, and estimated a sample average of 12 ug/m3 (micrograms per cubic meter). if 196 readings were taken, and the standard deviation of the sample measurements was 3.5 pg/m°, you are 99.7% confident that actual concentration of fine particulates at the school is __ o a. 5 ug/m3 - 19 pg/m3 ob. 11.25 pg/m– 12,75 ug/m3 o c. 11.5 mg/m3 - 12.5 mg/m3 o d. 1.5 ug/m3 - 22.5 pg/m3