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: if 7 ^ k = 2 , then 7 ^ ( 4 k + 2 ) = 
Options: a ) 729 , b ) 754 , c ) 784 , d ) 783 , e ) 108
[EX A]: c

[EX Q]: Problem: students at a school were on average 180 cm tall . the average female height was 170 cm , and the average male height was 184 cms . what was the ratio s of men to women ? 
Options: a ) 5 : 2 , b ) 5 : 1 , c ) 4 : 3 , d ) 4 : 1 , e ) 3 : 1
[EX A]: a

[EX Q]: Problem: in 10 years , a will be twice as old as b was 10 years ago . if a is now 9 years older than b , the present age of b is ? 
Options: a ) 39 yr , b ) 42 yr , c ) 45 yr , d ) 32 yr , e ) 50 yr
[EX A]:
a