Instructions Full Game: These are multiple-choice quizzes with four possible answer choices that include all questions in a given set.     
Identify the series which featured the following episode.

"The Towers of Zenith" (1990)

It was ranked 22nd on TV Guide's "100 Greatest Episodes of All-Time" list from 1997.
"Speed Racer"
"The Cosby Show"
"thirtysomething"
"On the Air"