1. The problem asks to name another pair of interior angles besides $a$ and $c$. 2. Interior angles are angles that lie between two lines and on the same side of a transversal. 3. If $a$ and $c$ are interior angles on one side of the transversal, then the other pair of interior angles are those on the opposite side of the transversal but still between the two lines. 4. Typically, if $a$ and $c$ are one pair, the other pair of interior angles are $b$ and $d$. 5. So, another pair of interior angles is $b$ and $d$.