Instructions: In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: if the sides of a triangle are 21 cm , 19 cm and 5 cm , what is its area ? 
Options: a ) 42.25 cm 2 , b ) 57.5 cm 2 , c ) 42.5 cm 2 , d ) 47.5 cm 2 , e ) 52.5 cm 2
Output:
d