The correct answer is (a). The weight of a human body is maximum at the poles and minimum at the equator. This is because the Earth is not a perfect sphere, but is slightly wider at the equator than it is at the poles. This means that the force of gravity is slightly weaker at the equator than it is at the poles.
Option (b) is incorrect because the weight of a human body is not the same at every place on the Earth’s surface. As explained above, the force of gravity is slightly weaker at the equator than it is at the poles. This means that a person would weigh slightly less at the equator than they would at the poles.
Option (c) is incorrect because the weight of a human body is not maximum at the equator. As explained above, the weight of a human body is slightly less at the equator than it is at the poles.
Option (d) is incorrect because the weight of a human body is not more on the mountains than planes. The force of gravity is slightly weaker at higher altitudes, so a person would weigh slightly less on a mountain than they would on a plane.