Question

multiple choice question
looping wire into a cylindrical coil (a solenoid) and passing a current through it produces a magnetic field because

the magnetic field lines produced by the wire are concentrated inside of the coil and have the same orientation
the coils start to become polarized and push against those on the other side of the loop producing a stronger magnetic field
electrons that happen to be in the air between the coils are accelerated in one direction

Explanation:

When a current - carrying wire is looped into a solenoid, each loop of the wire produces a magnetic field. The magnetic field lines inside the solenoid are nearly parallel, concentrated, and have the same orientation. This is due to the superposition of the magnetic fields from each individual loop.

• For the second option: Coils do not "polarize" in the sense described here. Magnetic fields in a solenoid are due to current - induced magnetic fields (from Ampere's law), not due to a "pushing" of polarized coils as described.
• For the third option: The magnetic field in a solenoid is not due to electrons in the air. The current in the wire (movement of electrons in the wire, not in the air) is what creates the magnetic field.

Answer:

the magnetic field lines produced by the wire are concentrated inside of the coil and have the same orientation