The following sentence has been divided into four segments. Identify the segment that contains a grammatical error.
She / did not watched / Frankenstein / last night.

Correct option is A

Explanation:
• When using “did not”, the main verb must be in its base form, not past tense.
• “Watched” should be replaced with “watch.”
Correct: She did not watch Frankenstein last night.
Grammar Rule:
• Did + not + base verb is used for negative sentences in the simple past tense.