B

Step 1: Understand that electric potential is defined by the work done in bringing a charge from infinity to a point in an electric field.
Step 2: The Earth is considered a large reservoir that can supply or absorb charge without experiencing a significant change in electric potential.
Step 3: The Earth behaves as a conductor because it allows charges to redistribute over its surface, thus maintaining a constant electric potential across its surface.
Step 4: As a result, the electric potential of the Earth is regarded as zero, providing a reference point for electric potential measurements.
Therefore, the correct answer is Option B.