Answer:
D. Omit they should have.
Step-by-step explanation:
Faulty parallelism happens when the parts of your series do not follow the same structure or format. Here's an example using the sentence about John:
John packed his pencils, pens, and put his notebooks in his backpack.
Adding the verb 'put' breaks up the flow of the sentence and makes it confusing and choppy. Instead of having a series with three nouns, the sentence now has two nouns followed by a verb.
If your writing has a series of phrases, the phrases should have a similar structure. For example:
Staying active is an important part of being healthy, being happy, and weight loss.
The first two phrases in the series follow the same structure ('-ing' verb), but the last one is a noun (weight loss). You could easily rewrite the sentence so that each phrase follows a similar structure:
Staying active is an important part of being healthy, being happy, and losing weight.
Hope this helps!