Answer:
d) All of the above.
Step-by-step explanation:
Magnetic field lines are formed around an object when there is a magnetic field around the object. From the question, we know that a bar magnet has an electric field. A current carrying loop has a magnetic field around it also. Current carrying straight wires and any conductor generally, carrying an electric current, produces a magnetic field around them. This magnetic field has lines of loos formed close to the material.