Which of the following is an example of a disciplinary action?

A disciplinary action refers to any measure taken in response to a violation of professional standards or regulations. In this context, all the options provided can be considered forms of disciplinary action, but particularly revoking a license stands out as a significant consequence for serious infractions.

Revoking a license directly removes an individual's ability to practice, which is a severe form of disciplinary action reflecting a failure to maintain required professional standards. Paying a penalty could also be deemed a form of disciplinary action, as it involves a financial consequence imposed by a regulatory body due to misconduct. Additionally, requiring training can also serve as a remedial action to address deficiencies in knowledge or professional behavior, ensuring that the individual conforms to acceptable standards moving forward.

Thus, each option illustrates a method by which disciplinary action can be executed, making the indication that all the choices are correct appropriate. In summary, the comprehensive nature of disciplinary actions encompasses penalties, revocation, and additional training as proactive measures to uphold professional integrity within the field.