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: find the principle on a certain sum of money at 5 % per annum for 3 1 / 5 years if the amount being rs . 870 ? 
Options: a ) rs . 700 , b ) rs . 780 , c ) rs . 750 , d ) rs . 1000 , e ) none of these

Output: c


Input: Consider Input: Problem: cost is expressed by the formula tb ^ 4 . if b is doubled , the new cost is what percent of the original cost ? 
Options: a ) 200 , b ) 600 , c ) 800 , d ) 1600 , e ) 50

Output: d


Input: Consider Input: Problem: if a * b * c = ( √ ( a + 2 ) ( b + 3 ) ) / ( c + 1 ) , find the value of 6 * 15 * 3 . 
Options: a ) 8 , b ) 5 , c ) 11 , d ) 3 , e ) 4


Output: d