Answer:
Contains. Should be contain instead
Step-by-step explanation:
The incorrect verb is contains. The verb that agrees with the subject and sentence should be contain because a rule of subject verb agreement states that subjects joined by "and" takes a plural verb, and a plural verb has no "s."
In this sentence, the subjects are the peanut butter and microwaveable popcorn. It is joined by "and" and as the rule states subjects joined by "and" take a plural verb which has no "s"