Mrs. Vijaya takes a total of 9 hours 50 minutes in walking a distance and running back to same place where she started. She could walk both ways in 12 hrs 20 minutes. The time taken by her to run both ways 1s:

A

7 hours 45 min

B

7 hours 35 min

C

7 hours 15 min

D

7 hours 20 min