Read the paragraph from the section "1. Define Small, Specific Goals."
A habit is a repeated behavior. Before you can develop a new habit, you'll need to define a small, specific behavioral goal. For example, instead of setting the goal of "being more organized" try "clean my room and vacuum every Sunday morning." This goal works because it's concrete. It's a behavior that you can repeat over and over until it becomes automatic – in other words, a habit.
How does this paragraph develop the central idea of the article?
a by elaborating on the types of habits most people want to form
b by emphasizing the difficulty of becoming more organized
c by explaining the first step toward achieving a habit you want
d by showing why large habit goals don't tend to work