Randy's grandmother enjoys exercising and is trying to encourage her grandchildren to stay active and fit.
What advice might she give to Randy about staying healthy?
a. "Randy, walking every day will have no impact on your health. Just join a sports team."
b. "Randy, don't walk too much or it will affect your immune system."
c. "Randy, you'll catch a cold if you walk outside, so only walk indoors."
d. "Randy, you should walk every day like I do if you want to live a long life!"