Answer:
(A)
Step-by-step explanation:
You need to share the main article, as well.
I am pretty sure it narrows down to (A) or (D), and based on the context, I would say it is going to be (A).
I have assumed that the main article is about piggybacking and how it influences to implement habits.
I might be able to help better if I had the article in my disposal.