Task: Question Answering
Input (English): Problem: mr . smith calculated the average of 10 3 digit numbers . but due to a mistake he reversed the digits of a number and thus his average increased by 19.8 the difference between the unit digit and hundreds digit of that number is : 
Options: a ) 2 , b ) 6 , c ) 5 , d ) 3 , e ) 4
Output (English): a