The correct answer is: C. She apologized for not being able to submit those papers.
The sentence “She said, ‘I am sorry, I am not able to submit those papers'” is an example of a direct quote. In a direct quote, the speaker’s exact words are enclosed in quotation marks. The speaker in this case is apologizing for not being able to submit the papers.
Option A is incorrect because it does not include the word “apologized.” Option B is incorrect because it does not include the word “for.” Option D is incorrect because it does not include the word “apologized” and it uses the word “exclaimed,” which suggests that the speaker was surprised or excited.