Task: Question Answering
Input (English): Problem: for a certain exam , a score of 58 was 2 standard deviations below mean and a score of 98 was 3 standard deviations above mean . what was the mean score r for the exam ? 
Options: a ) 74 , b ) 76 , c ) 78 , d ) 80 , e ) 82
Output (English): a