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: Consider Input: Problem: peter invested a certain sum of money in a simple interest bond whose value grew to $ 100 at the end of 2 years and further to $ 200 at the end of another 4 years . what was the rate of interest in which he invested his sum ? 
Options: a ) 50 % , b ) 25 % , c ) 10 % , d ) 30 % , e ) 18 %

Output: a


Input: Consider Input: Problem: the cost price of an article is 70 % of the marked price . calculate the gain percent after allowing a discount of 10 % . 
Options: a ) 13.6 % , b ) 28.6 % , c ) 35.6 % , d ) 42.3 % , e ) none

Output: b


Input: Consider Input: Problem: after decreasing 24 % in the price of an article costs rs . 836 . find the actual cost of an article ? 
Options: a ) 1667 , b ) 6789 , c ) 1200 , d ) 1100 , e ) 1421


Output: d