When a principal accepts the unauthorized acts of someone misrepresenting themselves as their agent, it is known as:

In the scenario where a principal accepts the unauthorized acts of someone who is misrepresenting themselves as an agent, the term that accurately describes this situation is "ratification." Ratification occurs when a principal effectively confirms or accepts the actions taken by an unauthorized agent, even if those actions were not initially sanctioned. This acceptance can happen either explicitly or implicitly, and it serves to validate the actions that were taken on behalf of the principal.

By ratifying the acts of the unauthorized agent, the principal assumes responsibility for those actions as if they had initially authorized them. This legal concept is critical in agency law because it allows for the possibility of a principal being bound by the acts of someone who may not have had the proper authority, provided the principal accepts those acts afterward.

The other terms present in the choices refer to different concepts. Affirmation typically involves confirming a prior agreement, revocation refers to the act of withdrawing authority or canceling a contract, and exoneration relates to freeing someone from responsibility or liability. None of these terms align with the provision of accepting unauthorized acts, further solidifying that ratification is indeed the correct answer.