Choose A, B, C, or D to indicate the sentence that best combines each pair of sentences in the following questions: The snowfall was very heavy in the capital city of England. All the trains there were cancelled. 

• A. 
  If it hadn’t been for the heavy snowfall, all the trains in the capital city of England would have been cancelled.
• B. 
  Only after all the trains in the capital city of England were cancelled dit it snow heavily.
• C. 
  So heavy was the snowfall that all the trains in the capital city of England were cancelled.
• D. 
  Had it snowed heavily, all the trains in the capital city of England wouldn’t have been cancelled.