Task: Question Answering
Input (English): Question: The arithmetic mean and standard deviation of a certain normal distribution are 15.5 and 1.5, respectively. What value is exactly 2 standard deviations less than the mean?

 Option A: 10.5

 Option B: 11

 Option C: 11.5

 Option D: 12

 Option E: 12.5
Output (English): Option E