What is wrong about this within$-$text editing? Focus on the format, not on the message.

"Dogs and cats can both be great pets $($Smith et$.$ al$.,2017)."$

A$."$et$.$ al$."$ should be italicized.

B$.$ The period should not appear after $"$et$",$ but should appear after $"$al$"$

C$.$ The period should not appear after $"$et$"$ or after $"$al$"$

D$.$ There should not be a comma after $"$al$."$