Answer:
A. An object in motion tends to stay in motion unless acting upon by an external force.
Explanation:
We have the statement, 'Seat belt save lives'.
Now, wearing seat belts are important because when an object is in motion, it stays in motion unless an external force is applied.
So, during some collision, seat belts act as the external force to provide a break to the body, which will help in preventing injuries.
Hence, we get that,
Newton says that we wear seat belts because, 'an object in motion tends to stay in motion unless acting upon by an external force'.