In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: the difference between a 7 digit number and the number formed by reversing its digit is not a multiple of 
Options: a ) 121 , b ) 11 , c ) 9 , d ) 10 , e ) 3
a

Problem: the unit digit in the product ( 784 x 618 x 917 x 463 ) is : 
Options: a ) 5 , b ) 9 , c ) 16 , d ) 2 , e ) 42
d

Problem: q and r are two - digit positive integers that have the same digits but in reverse order . if the positive difference between q and r is less than 30 , what is the greatest possible value of q minus r ? 
Options: a ) 23 , b ) 24 , c ) 25 , d ) 26 , e ) 27

e