In this question, look at the underlined part of each sentence. Below each sentence are given three possible substitutions for the underlined part. If one of them, i.e., $A, B$ or $C$ is better than the underlined part, If none of the substitutions improves the sentence, Thus a 'No improvement' response will be signified by the letter $D$. As the parties failed to reach any agreement, the meeting broke through.

• Correct answer
  A

  broke out
• B

  broke away
• C

  broke up
• D

  No improvement

Hence, the correct answer is option: 'A'.