Explanation:

- Option 1: able to watched

- This is the correct segment containing a grammatical error.

- The phrase "able to" should be followed by the base form of the verb.

- Correct: "able to watch"

- This is the correct answer.

- Option 2: the movie

- This is grammatically correct.

- The phrase is a noun phrase with no errors.

- Option 3: were not

- This is also correct and forms part of a negative past tense construction.

- Option 4: due to

- This phrase is correct and indicates the reason for not watching the movie.