In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: the area of a rectangular field is equal to 500 square meters . its perimeter is equal to 90 meters . find the width of this rectangle . 
Options: a ) 5 , b ) 10 , c ) 15 , d ) 20 , e ) 25
A: 
d