A 100 kg ball of lead rests next to a 10 kg rock. Which statement below is true?

Question

a. the lead ball and the rock have equal amounts of inertia
b. if the lead ball and the rock fell from the same height in a vacuum, the rock would hit the ground first because it is less massive.
c. on the moon both would have the samemass as on earth, but not the same weights as on earth.
d. because the lead ball has a larger mass than the rock, it will definitely have a larger volume than the rock