The answer is b because I said so
These lines are spoken by a captain who has been wounded in the war. He is relaying the information about Macbeth's brave fight against the enemy to King Duncan. He talks about how brave and valiant Macbeth was, so the audience can infer that he is a fierce warrior who will stop at nothing to ensure his win in a battle.
There are many factors that could hamper an effective communication. Some of those could be: social status (if you are talking to someone who has a more important status than yourself, it may happen that they are not interested in a communication with you), use of language (if you use inappropriate words, the conversation is not going to be successful), knowledge about the subject (if you don't know what you are talking about, the conversation is likely not going to continue), atmosphere/noise, cultural differences, disabilities, etc.
the underlined one and the second is is D look more carefully nad you can see it