Explanation:

- Option 1: You will not be allowed by me to ride the horse.

- This is a correct passive sentence. It conveys that the speaker is not permitting you to ride the horse.

- Correct Answer

- Option 2: Riding of the horse will not be allowed by me.

- This sentence is also correct. It uses a formal structure to express the same idea that you are prohibited from riding the horse.

- Option 3: You are not supposed to ride the horse by me.

- This sentence is awkwardly structured. It suggests expectation rather than permission. It's not a proper passive construction related to permission.

- Option 4: None of these

- This option would be correct if all previous options were inaccurate, which is not the case here.