$6\mathrm{.}33*$ Figure P$\mathrm{.}6\mathrm{.}33$ shows the image irradiance distributions arising when a monochromatic point source illuminates three different optical systems, each having only one type of aberration. From the graphs identify that aberration in each case and justify your answer.

Figure P$\mathrm{.}6\mathrm{.}33$a $($E$.$H$.)$