The correct option is B
3 hour 15 minutes
From 9:15 to 10:15, he takes 1 hour.
From 10:15 to 11:15, he takes 1 more hour.
From 11:15 to 12:15, again 1 hour.
and from 12:15 to 12:30, he takes 15 minutes.
So overall he takes, 1 hr + 1 hr + 1 hr + 15 minutes= 3 hr + 15 minutes.
that is 3 hour and 15 minutes.