Which of the following sentences has an INCORRECT subject-verb agreement?

The sentence "The debate team from Des Moines are going to state nationals" features an incorrect subject-verb agreement due to the singular noun "team." Although "debate team" includes multiple members, it is treated as a single unit in terms of grammar. Therefore, the correct verb form should be "is" instead of "are" to align with the singular subject.

In contrast, the other sentences present proper subject-verb agreement. In the first sentence, "a quarter" is treated as singular, matching with "care." In the second sentence, "flight crew" is a collective noun treated as a unit, thus "was" is appropriate. The third sentence correctly uses "appears" with the singular subject "choir." Each of these examples maintains the correct form of the verb with its subject, reinforcing the rules of subject-verb agreement effectively.