[QA] He was sorry he hadn’t said goodbye to her at the airport.

Question:

He was sorry he hadn’t said goodbye to her at the airport.

• A.
  He regretted not to say goodbye to her at the airport.
• B.
  He regretted not to saying goodbye to her at the airport.
• C.
  He regretted saying goodbye to her at the airport.
• D.
  He wished he had said goodbye to her at the airport.