Gerunds and tenses

Hello everyone. I have a question.

I'm wondering about how to correctly use gerunds in terms of tenses. Could you please evaluate the following three pairs of sentences depending on whether they are natural or not? Please also tell me if there are any items that are "unnatural but still acceptable."

(A) Hi, Tom. How have you been doing? I'm sorry for not replying to you sooner.
(B) Hi, Tom. How have you been doing? I'm sorry for not having replied to you sooner.

(C) It's impossible someone entered my room. I'm sure about locking the door.
(D) It's impossible someone entered my room. I'm sure about having locked the door.

(E) John admitted hurting Mary's feelings at the party.
(F) John admitted having hurt Mary's feeling at the party.