The fire- fighters made every effort to put off the flames. The building burned down completely.

A The building burned down completely though the fire- fighters made every effort to put off the flames.

B Had it not been for the fire- fighters’ every effort, the building would have burned down completely.

C Making every effort to put off the flames, the fire- fighters completely burned down the building.

D Since the fire- fighters made every effort to put off the flames, the building burned down completely.