Choose the option that best completes the sentence. The movie wasn't fantastic, was it? _____

To select the best option to complete the sentence "The movie wasn't fantastic, was it?" we need to understand the structure of a tag question. A **tag question** consists of a **statement** followed by a short question. The tag question is typically used to confirm something the speaker believes to be true. In English, the **tag** is generally formed by inverting the auxiliary verb and subject of the main sentence and is usually the opposite in form (affirmative vs. negative).

In this case, the statement is "The movie wasn't fantastic". The tag "was it?" is used to seek confirmation and implies that the speaker anticipates agreement. **Since the statement is negative ("wasn't"), the agreement or confirmation often expected is affirmative.**

Therefore, if you agree that the movie wasn't fantastic, you'd say "No, it wasn't" to confirm the negative statement because agreement to a negative statement is expressed with "no".

Thus, the correct option to complete the sentence is:
No, it wasn't.