Final answer:
The magnetic flux through a loop outside of a solenoid is zero because the magnetic field outside the solenoid is essentially zero.
Step-by-step explanation:
To find the magnetic flux through the loop due to the solenoid, we need to consider the properties of the magnetic field generated by a solenoid. As mentioned in the information provided, the magnetic field inside a solenoid is remarkably uniform and directed parallel to the solenoid's axis. Outside of the solenoid, particularly far from the ends, the magnetic field is essentially zero. Since the magnetic flux (Φ) through a loop is defined as the product of the magnetic field (B) and the area (A) through which the field is passing, and given that the magnetic field outside a solenoid is nearly zero, the magnetic flux through a loop that is outside the solenoid would also be nearly zero. Therefore, the answer to the student's question is b) Magnetic flux is zero.