Three rugs have a combined area of 200\:m^2 . By overlapping the rugs to cover a floor area of 140\:m^2, the area which is covered by exactly two layers of rug is 24\:m^2. What area of floor is covered by three layers of rug?
Answer Choices
A. 12\:m^2
B. 18\:m^2
C. 24\:m^2
D. 36\:m^2
E. 42\:m^2