Final answer:
The sentence contains an overly broad reference with the pronoun 'they', which is not clearly defined. Specifying the antecedent for 'they' would make the sentence clearer.
Step-by-step explanation:
The sentence in question contains an unclear reference, specifically an overly broad reference. This type of unclear reference occurs when it's not clear to what or whom the pronoun 'they' refers. In this sentence, 'they' could refer to the school district officials, but that is not explicitly stated. The sentence could be clearer if it specified who requires uniforms, for example, 'In this school district, the school administrators require uniforms for all grade levels above fifth grade.'