Instructions: In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: a book is bought for $ 60 and sold for $ 63 . what is the profit in percentage ? 
Options: a ) 3 , b ) 5 , c ) 7 , d ) 9 , e ) 11
Output:
b