Which of the following is an example of a classroom rule?

Respecting others is a fundamental principle that fosters a positive learning environment in the classroom. Establishing "respect others" as a classroom rule sets a tone for how students should interact with each other and with their teacher. When students understand the importance of respect, it encourages collaboration and reduces conflicts, which enhances the overall classroom experience.

In comparison, while the other options provide important guidance for specific classroom logistics or behaviors, they do not encompass the overarching ethical behavior expected in a community. For instance, instructions on how to turn in work, ask for help, or what supplies to bring focus more on procedural aspects rather than the foundational attitude and mutual regard that "respect others" entails. Thus, the answer highlighting respect emphasizes the core values that are vital for a conducive learning atmosphere.