Answer:
A. They help maintain balance on both sides of a sentence, keeping coordinating ideas in similar forms.
Step-by-step explanation:
The rules of parallelism apply to coordinating ideas by ensuring that they are presented in a consistent and balanced manner. This means that items in a list or series, for example, should be presented in parallel form, with matching grammatical structures and verb tenses. This helps to make the ideas easier to understand and more memorable for the reader or listener. Maintaining parallelism in coordinating ideas can also help to create a sense of balance and harmony, making the writing or speech more effective and persuasive.