A man takes 5 hrs 15 min to walk up to a certain point and then he decides to ride back. If he gains 2 hr when he rides both ways, i.e. back and forth; calculate the time he would take to walk both ways.

• A. 3 hrs and 15 minutes
• B. 7 hrs
• C. 3 hrs
• D. 7 hrs and 15 minutes