The answer is D, 32pi
The radius is half the diameter, which is 32. The circumference equation is
or 
So that gives you 32pi
Its A.
because if the base is 13 and 13 and the sides are 10 cm multiply and get A.
It can be written as: 1 T-Shirt per 5 people
If you have any further questions feel free to ask.
Hope this helps.
I would go with A. An estimate.
This may not be the right answer but Good Luck!