Explanation:

- Option 1: Valid contract

- Contingent contracts are indeed valid contracts. They are agreements that depend on the occurrence of a future uncertain event.

- Option 2: Illegal agreement

- An illegal agreement is one that involves activities that are against the law. Contingent contracts are not illegal as they are recognized by law.

- Option 3: Voidable contracts

- Voidable contracts are valid contracts but contain elements that may allow one party to void them. Contingent contracts are not inherently voidable; they become enforceable when the specified event occurs or does not occur.

- Option 4: None of the above

- This would apply if none of the options were correct, but it does not fit the description of contingent contracts.

Option 1: Valid contract is the correct choice.