Search your question and google and watch the first video and that should give you the answer!
Definitely not B or D. A is out of the question too, so I think it's C
Fragment, it doesn't have a predicate/verb.
Answer:
She shouldn't use a different car each trial, it makes the results less valid. Instead she should use the same car, and should just clean off the car after each trial.
I am positive that it is asset.
