Settle, for example : if you resolve a problem you have settled the problem.
Answer: C) I had done that to her.
Explanation:
A remorseful tone is used when someone feels sad or guilty over what he/she has done. The speaker, in this case, is consumed by guilt when he/she realizes that his/her mother has become old. The speaker does not blame the terrorists, or the Department of Homeland Security, but himself/herself. The sentence "I had done that to her" shows the speaker's acknowledgement of his/her mistakes.
