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: approximately how many cubic feet of water are needed to fill a circular swimming pool that is 100 feet across and 4 feet deep ? 
Options: a ) 15000 , b ) 30000 , c ) 50000 , d ) 70000 , e ) 90000
Example Output: b

Example Input: Problem: rectangle a has sides a and b , and rectangle b has sides c and d . if a / c = b / d = 4 / 5 , what is the ratio of rectangle a ’ s area to rectangle b ’ s area ? 
Options: a ) 5 / 4 , b ) 25 / 16 , c ) 4 / 5 , d ) 16 / 25 , e ) 16 / 5
Example Output: d

Example Input: Problem: in right triangle abc , ac is the hypotenuse . if ac is 20 and ab + bc = 50 , what is the area of the triangle abc ? 
Options: a ) 225 , b ) 525 , c ) 25 √ 2 , d ) 200 , e ) 200 √ 2
Example Output:
b