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'.

Input: Consider Input: Problem: if - 3 x + 2 y = 28 and 3 x + 6 y = 84 , what is the product of x and y ? 
Options: a ) 264 . , b ) 428 , c ) 0 , d ) 462 , e ) 642

Output: c


Input: Consider Input: Problem: 5357 x 51 = ? 
Options: a ) 273232 , b ) 273243 , c ) 273247 , d ) 273250 , e ) 273207

Output: e


Input: Consider Input: Problem: what is the units digit of ( 493 ) ( 915 ) ( 381 ) ( 756 ) 
Options: a ) 0 , b ) 1 , c ) 4 , d ) 5 , e ) 6


Output: c