You will be given a definition of a task first, then some input of the task.
In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a brick measures 20 cm * 10 cm * 7.5 cm how many bricks will be required for a wall 28 m * 2 m * 0.75 m ? 
Options: a ) 28000 , b ) 27908 , c ) 78902 , d ) 25000 , e ) 27991
Output:
a