The Total cost of flooring a room at Rs.8.50 per square meter is Rs.510. If the length of the room is 8km it’s breadth is__________?

The Total cost of flooring a room at Rs.8.50 per square meter is Rs.510. If the length of the room is 8km it’s breadth is__________?

A. 7.5m
B. 8.5m
C. 10.5m
D. 12.5m