Answer: Hello there! I believe the answer you're looking for is B: Worried and unsure of how to get a good deal on his first car, Marty asked his parents for advice.
Explanation: This is the proper way to use a clause in a sentence, as the subject (Marty) is experiencing or feeling everything that comes before the comma.
Another way to think of this sentence is like this: Marty is worried and unsure of how to get a good deal, so he will ask his parents for advice.
I hope this helps! :)