Earthworm have bones Some children confuse earthworms, which are invertebrates and have no bones, with snakes which are vertebrates and do have a bony skeleton and many ribs.
To respond to the question, we need the data provided with the question.
I can't eliminate answers. Some of them are just wrong. A is incorrect. There is no such thing as a 1 pole magnet.
I wouldn't use B. If it is just a bar it is not a magnet.
C is the traditional answer
D is a space filler. It is just there to occupy a letter.
Answer: inertial mass
The measure of resistance to motion by an object is the objects inertial mass
