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 man gains 10 % by selling an article for a certain price . if he sells it at double the price , the percentage of profit will be . 
Options: a ) 130 % , b ) 120 % , c ) 150 % , d ) 160 % , e ) 170 %
Output:
b