The department should have a complaint form stating that the person signing the complaint does affirm under penalty of __________ that the facts contained therein are truthful.

The correct answer is perjury because this term refers specifically to the act of lying or making false statements under oath. In many legal and formal contexts, when someone affirms that their statements are truthful under the penalty of perjury, they are acknowledging that they are providing information that is supposed to be accurate and truthful, and they understand that doing otherwise can lead to serious legal consequences.

Using perjury in this context emphasizes the seriousness of the complaint process. It serves to underscore that providing false information can result in legal repercussions, which promotes honesty and accountability. Other terms such as fraud, misrepresentation, and liability, while related to dishonesty or legal issues, do not carry the same specific implications of making a false statement under oath as perjury does. Thus, the use of perjury appropriately captures the legal weight of affirming the truthfulness of the information provided in a complaint form.