Task: Question Answering
Input (English): Problem: the class mean score on a test was 50 , and the standard deviation was 15 . if jack ' s score was within 2 standard deviations of the mean , what is the lowest score he could have received ? 
Options: a ) 20 , b ) 31 , c ) 45 , d ) 90 , e ) 89
Output (English): a