We can put the correct sentence to be:
B: I don't know. I haven't seen that movie.
What is sentence?
A sentence is known to be a group of words that are used to make a complete thought. It usually have a subject and a predicate.
We can see that since the reply of the question started with "I don't know", therefore, it should end with "I haven't seen..."
Learn more about sentence on https://brainly.com/question/8823021
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