Choose the grammatically correct sentence.

The correct answer is Option (3) - Grapes cannot be gathered from thistles.

The grammatically correct sentence is: Grapes cannot be gathered from thistles.

This sentence uses the correct verb form "cannot be gathered," which is the passive form of "cannot gather."
 "Grapes" is the subject, "cannot be gathered" is the verb phrase, and "from thistles" is the prepositional phrase indicating the source.