The total cost of flooring a room at ₹8.50 per square metre is ₹510...

The total cost of flooring a room at ₹8.50 per square metre is ₹510. If the length of the room is 8 metres, then its breadth is

A. \(7.5\mathrm{m}\)

B. \(8.5\mathrm{m}\)

C. \(7\mathrm{m}\)

D. \(7.8\mathrm{m}\)