During which period of development do people typically face new issues,
which may lead to eating disorders or substance abuse?
a. middle adult hood
b. early adulthood
c. adolescence
d. school age

I'd say C- Adolescence because it ranges from ages 10-19, which is the most common age range for eating disorders to occur. Do your research though, because I also sort of agree with B, but technically eating disorders can happen at any age. Still, I'd say C because eating disorders happen around the teenager age, due to stress and body shaming. 
Love your body, and good luck on your test!