Answer:
C
[tex] \: \\ diameter = 4ft \\ \: raduis \: = \frac{diameter}{2} \\ raduis = \frac{4ft}{2} = 2ft \\ c = 2\pi \: r \\ c = 2\pi2ft \\ c = 4\pi \: ft \\ c = 4 \times 3.14 = 12.56ft[/tex]