A protagonist and an antagonist _____

Juice this one isn't as obvious though some of us wish you could have proffered a guess, explaining why, as it might help us help you

Although Teach probably wants you to select no. 3, any of the remaining three could be okay depending on the specific issue and how it's presented to whom. My Better Half, who is much smarter than I, agrees

However, I like no. 1 also. According to the general principle that nothing is entirely anything while everything is partly something else, only the slightest shift in either's position could result in an agreement. For instance Pro might not be Ant's opponent but the supporter in the his presentation

Eg, Ant is decrying a shortage of water, blaming it on incompetent government while Pro, without offering a specific opinion himself, persuades us to listen