Final answer:
At the start of the saxophone solo in "Civilization Day," a key change occurs. The provided mixed-up answer choices suggest content from an unrelated field, showing contextual mismatch.
Step-by-step explanation:
At the beginning of the saxophone solo in "Civilization Day," the correct event that takes place is c. Key changes. The use of a key change at the start of a solo is a technique often employed in jazz to inject a new mood or energy into the piece. However, this question seems to contain mixed-up answer choices, as they could pertain to different aspects of musical performance. References to the width of the spaces between the bands are not relevant to musical solos and appear to be out of context or could refer to a different topic entirely, such as gel electrophoresis in biology.