Respuesta :
This would be Newton's first law of motion as it is a factual statement based on observations.
The statement that 'an object at rest will continue to stay at rest and an object in motion will stay in motion in same direction and at constant speed unless some external force acts on the object' is a law of motion. This statement describes a fact which is base don the observations made by Newton. It is universally true and hence, it is not a hypothesis, or theory but a law.
Hence, the correct answer is 'law of motion because it is factual and based on observations'.