A root word has no prefix or suffix and is the most basic part of a word. The prefix of the word 'unreasonable' is 'un'. The root word is 'reasonable.'
Language is a system of signs represrnting ideas to convey a message. Those symbols, which are words can be arbitrary, ambiguous, abstract representations of other phenomena. Words are not intrinsically connected to what they represent. Meanings of words can shift over time. The arbitrary character allows us to invent new words.
Language is ruled guided, simply put, verbal communication is guided by unspoken but broadly understood rules.
So I would say that option A, C and D are correct.
Meanwhile, I think that option B is incorrect since a mean of communication is understood as the tool and technology employed in order to convey a message, exchange information, ideas.
The correct answer is - Different sound effects can be used to enhance the action and excitement of the story.
One difference between reading a play and actually watching it is that while watching a play, you can hear various sounds that you would normally not be able to hear while reading that particular play. Watching a play engages most of your senses (sight, hearing, etc) whereas while reading, you are only using your sight (and imagination).
