To create parallel structure in the sentence, which phrase would best replace the words "when plays are tragic"?
plays that are funny are more popular than when plays are tragic.
tragedy in plays
plays being tragic
plays that are tragic
in tragic plays

The answer to your question would be that to create a parallel structure in the sentence, the phrase that would replace the words "when the plays are tragic" best is the following one: Plays that are tragic.

Parallel structure, also known as parallelism, is the repetition of a grammatical construction within in a sentence. In this case, the construction repetead is the whole NP (the noun head and its modifiers: plays that are funny and plays that are tragic)

rivalry

explanation: