Select the most appropriate synonym of the given word.
Interfere

The word 'Interfere' means to prevent a process or activity from being carried out properly, or to get involved in a situation where one is not wanted.
Let's check the meanings of the options:

Allow: Give permission to do something. (Antonym)

Assist / Help: Provide resources or help to achieve something. (Antonyms)

Obstruct: Block, hinder, or get in the way of something. (Synonym)

Thus, 'Obstruct' is the correct synonym.