TASK DEFINITION: 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: 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

SOLUTION: d

PROBLEM: Problem: how many multiples of 2 are there between 10 and 52 , 10 and 52 inclusive ? 
Options: a ) 27 , b ) 25 , c ) 24 , d ) 21 , e ) 22

SOLUTION: e

PROBLEM: Problem: what is the greatest prime factor of 2 ^ 8 - 1 ? 
Options: a ) 11 , b ) 13 , c ) 17 , d ) 19 , e ) 23

SOLUTION:
c