In the figure shown below, $\mathrm{MN}$ is a plane mirror. $\mathrm{W}, \mathrm{X}, \mathrm{Y}$ and $\mathrm{Z}$ are four children. Mark the positions of the reflections of $\mathrm{W},\hspace{0.17em}\mathrm{X}, \mathrm{Y}$ and $\mathrm{Z}$ in the mirror. Answer the following questions.

a. Which child/children can see their own images in the mirror$?$

b. Can child $\mathrm{W}$ see the images of $\mathrm{X}, \mathrm{Y}$ and $\mathrm{Z}$ in the mirror$?$