His friends supported and encouraged him. He did really well in the competition.

A. Such were his friends’ support and encouragement that he couldn’t do really well in the competition.

B. Had it not been for his friends’ support and encouragement, he couldn’t have done so well in the competition.

C. No matter how much his friends supported and encouraged him, he couldn’t do well in the competition.

D. If his friends had given him support and encouragement, he could have done really well in the competition.