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'.

[EX Q]: Problem: a student chose a number , multiplied it by 8 , then subtracted 138 from the result and got 102 . what was the number he chose ? 
Options: a ) 30 , b ) 120 , c ) 130 , d ) 140 , e ) 150
[EX A]: a

[EX Q]: Problem: if n is a natural number , then ( 6 n ^ 2 + 6 n ) is always divisible by 
Options: a ) 6 only , b ) 6 and 12 both , c ) 12 only , d ) 18 only , e ) 12 and 18 both
[EX A]: b

[EX Q]: Problem: the unit digit in the product ( 115 * 297 * 196 * 108 ) is : 
Options: a ) 2 , b ) 7 , c ) 6 , d ) 0 , e ) 8
[EX A]:
d