[QA] Arthur entered the store. Then, he realized that there was danger.

Question:

Arthur entered the store. Then, he realized that there was danger.

• A.
  Not until Arthur entered the store, he realized that there was danger.
• B.
  It was not until Arthur entered the store then, he realized that there was danger.
• C.
  Only when he entered the store then he realized that there was danger
• D.
  Only after entering the store did Athur realize that there was danger