Evaluate ∮CF⋅dr\oint_C \mathbf{F} \cdot d\mathbf{r}∮CF⋅dr where F=⟨−y,x⟩\mathbf{F} = \langle -y, x \rangleF=⟨−y,x⟩ and CCC is the unit circle oriented counter-clockwise.
000
2π2\pi2π
π\piπ
111