I'm sorry about that

[fire fly]

Hi, everybody!
Could you please help me with this question:
- "I'm sorry about that!" - "________"
A. That's right B. Of course C. You're welcome D. It's OK
I personally choose A. That's right. How about "D. It's OK" I think it is fine here, too. Many thanks in advance.:roll:

 

[Raymott]

Hi, everybody!
Could you please help me with this question:
- "I'm sorry about that!" - "________"
A. That's right B. Of course C. You're welcome D. It's OK
I personally choose A. That's right. How about "D. It's OK" I think it is fine here, too. Many thanks in advance.:roll:

As Gillnetter almost said, A is wrong.
Only D works.