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: if the area of a circle is 16 pi square feet , find its circumference . 
Options: a ) 8 pi feet , b ) 28 pi feet , c ) 38 pi feet , d ) 48 pi feet , e ) 58 pi feet
Example Output: a

Example Input: Problem: a lady grows broccoli in her garden that is in the shape of a square . each broccoli takes 1 square foot of area in her garden . this year , she has increased her output by 79 broccoli when compared to last year . the shape of the area used for growing the broccoli has remained a square in both these years . how many broccoli did she produce this year ? 
Options: ['a ) 1600', 'b ) 1500', 'c ) 1650', 'd ) 1700', 'e ) can not be determined']
Example Output: a

Example Input: Problem: the side of a rhombus is 26 m and length of one of its diagonals is 20 m . the area of the rhombus is ? 
Options: ['a ) 488', 'b ) 429', 'c ) 418', 'd ) 480', 'e ) 410']
Example Output:
d