Describe the set of all points that satisfy $x = -6$ if the solution set is plotted
(a) in $\mathbb{R}$, the $x$-axis.
(b) in $\mathbb{R}^2$, the $xy$-plane.
(c) in $\mathbb{R}^3$, $3$-space with variables $x$, $y$, and $z$.

Explain your answer using complete sentences with correct grammar, spelling, and punctuation.