Answer:
C
Explanation:
Argument
Passage 1 is not precise enough. The second passage shows how long it takes to form a habit and the upshot is that it varies from about 18 days to not being able to form the habit at all.
I don't think D is the answer. It is not inaccurate. The first passage just gets stuck in a rut and doesn't get out.
The first passage looks like it is precise and informed. It really isn't. It just has steps which makes it look precise and informed. Not B
It is clear enough, just not as clear as the second passage. Not A
Which leaves us with C. I would pick it, but don't be surprised if it is one of the other choices. I just think it gets in a rut and stays there.