In this task, you need to provide the correct option for a given problem from the provided options.

Problem: a small island country of 5000 people has an emigration and immigration statistic per 500 persons of 50.4 and 15.4 respectively . how long will it take for the population to be half of its current number .
Options: a ) 6.8 , b ) 8.5 , c ) 6.1 , d ) 9.1 , e ) 7.14
e