Correct option is D
The sentence "She forced herself to eat" is grammatically correct.
• "Forced" is the correct past tense form of "force," used here to indicate compulsion.
• "Herself" is an appropriate reflexive pronoun referring back to the subject "She."
• "To eat" is an infinitive that correctly acts as the object of the verb "forced," indicating the action she compelled herself to do.
• The structure and elements of the sentence are correct, with no grammatical errors.