Final answer:
Sentence 20 is grammatically correct as written, maintaining appropriate punctuation and phrase structure to convey the personal impact of scents on memory recollection. No changes are needed. Option number d is correct.
Step-by-step explanation:
The question pertains to sentence 20: "Whatever the case may be, I know for myself that certain smells today always take me back to times that were innocent and full of exploration and wonder." To answer if any changes need to be made, the sentence structure should be analyzed for grammatical correctness and clarity.
In this sentence, the phrase "certain smells today" correctly demonstrates the influence smells of the present have in recalling past experiences. The current punctuation is appropriate as it reflects a pause before sharing the personal impact of those scents. Therefore, the correct answer would be D) No change is needed in sentence 20.