15. A flag is in the shape of a right-angled triangle, as shown, with the horizontal and vertical sides being of length $72 \mathrm{~cm}$ and $24 \mathrm{~cm}$ respectively. The flag is divided into 6 vertical stripes of equal width.
What, in $\mathrm{cm}^{2}$, is the difference between the areas of any two adjacent stripes?

A 96
B 72
C 48
D 32
E 24