In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: the length of a rectangle is increased by 40 % while its width is halved . what is the % change in area ? 
Options: ['a ) 25 %', 'b ) 30 %', 'c ) 50 %', 'd ) 65 %', 'e ) 70 %']
Example Output: b

Example Input: Problem: two cubes of their volumes in the ratio 343 : 729 . the ratio of their surface area is : 
Options: a ) 7 : 9 , b ) 2 : 5 , c ) 3 : 5 , d ) 1 : 5 , e ) 4 : 5
Example Output: a

Example Input: Problem: three fifth of the square of a certain number is 126.15 . what is the number ? 
Options: ['a ) 210.25', 'b ) 75.69', 'c ) 14.5', 'd ) 145', 'e ) 150']
Example Output:
c