20) How do I solve this?

A clinical trial is being performed to establish the effective dose for a new medication. The data is normally distributed with a mean of u = 90 mg and standard deviation of o - 28 mg. How many standard deviations from the mean would a dose of 6 mg be? (Answers are rounded) O a) 3 standard deviations below the mean O b) 0.24 standard deviations above the mean O c) 3 standard deviations above the mean O d) 0.24 standard deviations below the mean