Four cows are tied at 4 corners (one at each corner) of a rectangular field of length 30 m and width 20 m. The length of the rope is 7 m. What is the area of the field that cows CANNOT graze? (Use $$\pi = \frac{22}{7}$$)

A

424 $$m^{2}$$

B

434 $$m^{2}$$

C

414 $$m^{2}$$

D

446 $$m^{2}$$