Explanation:

- Valid: This means the transaction is legally binding and enforceable. A collateral transaction is not considered valid if it's connected to an illegal agreement.

- Voidable: A voidable contract is valid until one party chooses to void it. However, a collateral transaction to an illegal agreement doesn't fall into this category.

- Void: This refers to a transaction that has no legal effect from the start. Collateral transactions to illegal agreements are typically considered void.

- Uncertain: This implies the legality is not clear-cut, but the law generally considers collateral transactions to illegal agreements as void.

Correct Answer: Void — Option 3.