Until test gravity

Why would a heavier book feel lighter on the Moon compared to Earth?
A.Because the Moon is smaller than Earth

B. Because the Moon has less gravity than Earth
C. Because there is no atmosphere on the Moon
D.Because the book loses mass on the Moon

B. Because the Moon has less gravity than Earth

The force of gravity on the Moon is only about 1/6th of the force of gravity on Earth. This means that objects on the Moon weigh less compared to Earth, making a heavier book feel lighter on the Moon.