Write an event showing Misplaced Modifier

The section under which we would be most likely to find information about reasons why teens start smoking is:

A. Factors Associated with Youth Tobacco Use

Explanation:

The different sections of the article will bring different types of information, even if they are all related to tobacco use by teens. If we are looking to find the reasons why teens start smoking, the section that will certainly mention them will be "Factors Associated with Youth Tobacco Use," which is basically restating what we are looking for, but with more formal words. When you mention factors associated with something, you are talking about the reasons or motives behind that something, that is, its causes.