C. either a or b
You can't just slam on the break on a motorcycle because you could go flying off. And on a motorcycle you have no walls or airbags to protect you.
Answer:
what are the words to choose from?
It probably has something to do with how the moon goes around the earth due to the gravitational pull and how an apple falls because of gravity as well. Even though the moon isn't falling onto the earth, they are still both following a set of rules that have to do with gravity.