Explanation:

- If B sends a proposal to A through a parrot, the parrot simply acts as a messenger.

- Law recognizes communication of proposals through different means—letters, phones, or even through a messenger.

- As the parrot is only delivering what B wants to convey, and there is no requirement that the messenger must be human, the proposal is considered properly communicated.

- *Option 1: Valid* (Correct)

- Communication of offer is valid, regardless of the medium, if content is correctly delivered.

- Option 2: Void

- Void means it has no legal effect, but this is not the case here as the communication is intact.

- Option 3: Unlawful

- The act is not illegal, so this does not apply.

- Option 4: Illegal

- No legal prohibition on delivering proposals through non-humans.