instruction:
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'.
question:
Problem: the unit digit in the product ( 891 * 781 * 912 * 463 ) is : 
Options: a ) 2 , b ) 5 , c ) 6 , d ) 8 , e ) 10
answer:
c


question:
Problem: gold is 19 times as heavy as water and copper is 9 times as heavy as water . in what ratio should these be mixed to get an alloy 15 times as heavy as water ? 
Options: a ) 3 : 2 , b ) 3 : 8 , c ) 5 : 7 , d ) 3 : 7 , e ) 3 : 6
answer:
a


question:
Problem: what is the smallest number which when increased by 3 is divisible by 18 , 70 , 100 and 21 ? 
Options: a ) 5037 , b ) 5447 , c ) 5867 , d ) 6297 , e ) 6617
answer:

d