4. What connection does the author draw between head
hits and white-matter changes?
A. Head hits that lead to concussions cause white-
matter changes.
B. Less severe head hits cause more white-matter
changes than severe head hits.
O C. Head hits of lesser as well as of greater severity can
cause white-matter changes.
O D. Less experienced athletes are more likely to sustain
head hits and white-matter changes.