Final answer:
Considering the gravitational pull, the rock dropped from 1 meter on the moon, which has about one-sixth of Earth's gravity, would take longer to fall than a rock dropped from the same height on Mars, with a gravity over one-third of Earth's.
Step-by-step explanation:
The question asks which would take longer to fall: a rock dropped from 1 meter on the moon or a rock dropped from 1 meter on Mars. To solve this, we consider the acceleration due to gravity on both celestial bodies. As the moon's gravity is about one-sixth of Earth's and Mars's gravity is a little over one-third of Earth's, the rock on the moon has a smaller gravitational pull accelerating it. Consequently, the rock on the moon would take longer to fall compared to the rock on Mars. Therefore, the correct answer is (a) Rock on the moon.