Mark the letter A, B, C, or D to indicate the sentence that best combines each pair of sentences in the following questions.
He didn’t focus more on his training. He left behind in the competition.
A. If he had focused more on his training, he wouldn't have left behind in the competition.
B. If he had focused more on his training, he would have left behind in the competition.
C. If he had focused more on his training, he cann't have left behind in the competition.
D. If he focused more on his training, he couldn't leave behind in the competition