Explanation:

- Option:1, This document

- This is the subject of the sentence. There is no grammatical error here.

- Option:2, No error

- This suggests that there is no error in the sentence, which is not accurate in this case.

- Option:3, by two persons

- This phrase indicates the agency or doers of the action. It is correct in this context.

- Option:4, has signed

- The phrase should be "has been signed" to correctly form the passive voice. Using "has signed" incorrectly suggests the subject performs the action.