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

Problem: a garrison of 400 men had a provision for 31 days . after 28 days 300 persons re - enforcement leave the garrison . find the number of days for which the remaining ration will be sufficient ? 
Options: a ) 65 days , b ) 45 days , c ) 10 days , d ) 16 days , e ) 12 days
e