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'.

[Q]: Problem: robert ate 13 chocolates , nickel ate 4 chocolates . how many more chocolates did robert ate than nickel ? 
Options: a ) a ) 4 , b ) b ) 7 , c ) c ) 9 , d ) d ) 5 , e ) e ) 2
[A]: c


[Q]: Problem: when 1 / 10 % of 4,000 is subtracted from 1 / 10 of 4,000 , the difference is 
Options: a ) 50 , b ) 200 , c ) 396 , d ) 398 , e ) 400
[A]: c


[Q]: Problem: how many positive even integers less than 100 contain digits 7 or 9 ? 
Options: a ) 16 , b ) 17 , c ) 18 , d ) 19 , e ) 10
[A]:
e