When an agency is created for illegal purposes, the agency is considered:

An agency created for illegal purposes is considered voidable because it does not have the necessary legal foundation to be binding. Essentially, any contract or agreement that supports an illegal act is not recognized by the law as valid. In this case, the agency lacks legal standing due to the nature of its purpose.

While some agreements can be voidable, meaning they may be affirmed or voided at the discretion of one party, in the context of illegal purposes, it implies that such an arrangement cannot be enforced in a court of law. This is because enforcing an agency based on illegal aims would contradict public policy principles, which aim to prevent the judiciary from supporting unlawful conduct.

Other options like valid, enforceable, or contradictory do not accurately represent the nature of an agency born from illegality. A valid agency would imply it is legally recognized, and enforceable suggests it can be upheld in court, neither of which is true in this instance. The term 'contradictory' doesn't provide a clear legal stance in this context, as it does not convey the idea of legality or enforceability in agency law as effectively as voidable does.