Explanation:

Sure, here's an explanation for each option:

- Option 1: To that extent void.

- In many jurisdictions, agreements restraining trade are generally considered void to the extent of restraint. Courts typically do not enforce contracts that significantly restrict a person's right to work.

- Correct Answer

- Option 2: Voidable at the option of the party who has been restrained.

- A voidable contract is one where a party has the option to enforce or void the contract. Restraints of trade are usually considered void, not voidable.

- Option 3: Valid and enforceable at law.

- Generally, agreements restraining a person from exercising a lawful trade are not valid and enforceable unless they are reasonable in scope, geography, and time.

- Option 4: Illegal.

- While such agreements might go against public policy, they are typically seen as void rather than illegal, as illegality can have criminal implications.

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