Four horses are tethered at four corners of a square plot of side 14 m so that the adjacent horses can just reach one another. There is a small circular pond of area 20 $$m^2$$ at the centre. Find the ungrazed area.

A

$$22 m^2$$

B

$$42 m^2$$

C

$$84 m^2$$

D

$$168 m^2$$