The equation of set of lines which are at a constant distance of 2 units from the origin and$\alpha$is angle made by perpendicular from origin is

• A

  $\mathrm{x}+\mathrm{y}+2=0$

• B

  $\mathrm{x}+\mathrm{y}+4=0$

• C

  $xcos\alpha \mathit{+}ysin\alpha \mathit{=}\mathit{2}$

• D

  $\mathrm{xcos\alpha }+\mathrm{ysin\alpha }=\frac{1}{2}$