Which rule best supports parallel structure in a list across multiple items?

• A. Use consistent grammatical form for items in a list.
• B. Mix noun, verb, and adjective forms in the same list.
• C. Omit conjunctions to save space.
• D. Add a comma after every item including the last.

Answer: (A)

Parallel structure keeps items in a list aligned by using the same grammatical form for each part. The best rule to support this is to use consistent grammatical form for items in a list. When every item is the same type—whether all nouns, all verb phrases, or all gerunds—the list flows smoothly and reads clearly. For example, “She enjoys hiking, biking, and kayaking” sounds balanced because each item is a noun form of activity, and “She plans to read, write, and edit” stays even because each item is an infinitive verb phrase.

If you mix forms—like “to read, reading, and to write”—the rhythm breaks and the sentence becomes awkward. Choices about punctuation, such as adding a comma after every item including the last, don’t fix this issue; that’s a matter of style or serial comma usage, not of keeping the same form across list items. So the consistent form across all items is what truly preserves parallelism and makes the writing clearer.