You will be given a definition of a task first, then some input of the task.
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'.

Problem: a sum amounts to rs . 3969 in 2 years at the rate of 5 % p . a . if interest was compounded yearly then what was the principal ? 
Options: a ) s . 3600 , b ) s . 5000 , c ) s . 4500 , d ) s . 4800 , e ) s . 5800
Output:
a