Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
He had just entered the house. The police arrested him at once.
A.Hardly he had entered the house when the police arrested him.
B.Immediately had he entered the house when the police arrested him.
C.The police immediately arrested him as soon as he’s entered the house.
D.No sooner had he entered the house than the police arrested him.