In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Input: Consider Input: Problem: a retailer bought a hat at wholesale and marked it up 60 % to its initial price of $ 24 . by how many more dollars does he need to increase the price to achieve a 100 % markup ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7

Output: d


Input: Consider Input: Problem: if a person walks at 20 km / hr instead of 10 km / hr , he would have walked 20 km more . the actual distance traveled by him is : 
Options: a ) 20 km , b ) 56 km , c ) 60 km , d ) 70 km , e ) 80 km

Output: a


Input: Consider Input: Problem: in the coordinate plane , points ( x , 1 ) and ( 12 , y ) are on line k . if line k passes through the origin and has slope 1 / 2 , then x + y = 
Options: a ) 4.5 , b ) 7 , c ) 8 , d ) 11 , e ) 12


Output: c