Which of the following reflects professionalism in a substitute teacher's conduct?

Maintaining high standards of values and ethics is crucial for a substitute teacher, as it establishes a foundation of trust and credibility within the educational environment. Professionalism is reflected in the way a substitute teacher interacts with students, staff, and the school community. Upholding strong ethical standards ensures that the substitute teacher acts in a manner that fosters respect, responsibility, and integrity, which are essential qualities in any educational setting. This approach not only benefits the teacher's reputation but also positively influences the students' learning experience and the overall school climate.

In contrast, other options such as establishing relationships only with students limit the scope of professionalism to a narrow focus. Wearing casual clothing might conflict with expectations for professional attire, thus not aligning with the image of professionalism. Disregarding school policies clearly undermines the authority of the educational institution and disrupts the learning environment, which is contrary to the expectations of a professional educator. Therefore, the choice that emphasizes maintaining high standards of values and ethics is the most reflective of professionalism in a substitute teacher's conduct.