Which of the following actions would undermine one's professionalism?

Responding defensively in criticism can significantly undermine one's professionalism because it reflects an inability to accept feedback and engage constructively in a discussion. When individuals become defensive, they may shut down opportunities for growth or learning that constructive criticism typically offers. Instead of fostering open communication or demonstrating maturity in handling challenges, defensiveness can create a hostile environment and damage relationships with colleagues and stakeholders.

In contrast, adhering to ethical standards, communicating effectively and respectfully, and teaching others with respect and dignity all enhance professionalism. These actions promote trust, collaboration, and a positive workplace culture, demonstrating a commitment to personal and professional growth as well as respect for others.