The length and the breadth of the floor of a room is 20 ft. and 10 ft respectively. Square tiles of 2 ft. dimension having three different colours are placed on the floor. The first row of tiles on all sides is of black colour, out of the remaining one-third is of white colour and the remaining are of blue colour. How many blue Coloured tiles are there?

• A. 16
• B. 32
• C. 48
• D. 24