The answer is, “Complementary medicine is treatments that are used along with standard medical treatments but are not considered to be standard treatments. One example is using acupuncture to help lessen some side effects of cancer treatment. Alternative medicine is treatments that are used instead of standard medical treatments.”
It’s B because traveling isn’t important.
Cardiovascular system has to do with the heart, so anything to reduce the risk of that system (including the heart, bloodstream etc.) would be the answer for you. So just using Process of elimination:
A) Has to do with external exposure. <em>No</em><em />
B) Keeping hands clean <em>No</em><em />
C) Avoiding cigarette smoke <em>Yes</em>
D) Keeping your vaccinations up to date <em>No</em><em />
So your answer is C.