I like the wood colored Cartesian plane.
Parallel lines have the same slope and the constant is set by the particular point the parallel passes through.
So our equation is
[tex]y = - \frac 1 3 x + b[/tex]
and we solve for b by plugging in (0,-2). So b=-2, the given y intercept.
[tex]y = - \frac 1 3 x - 2[/tex]
Choice D