Answer:
The best way to determine whether a planet has crust composed of plates that move is if it has chains of volcanoes along continental coastlines.
Explanation:
A is not correct because the condition of the water depends on the temperature of the planet and its atmosphere.
B is not correct because the iron-rich rocks may just be an ancient remnant of volcanic activity, but in general, it is the most common metal found in the crust, so it is not a good indicator.
C is correct because the chains of volcanoes along the coastlines indicate that there are subduction zones, meaning that there are tectonic plates that move.
D is not correct because the deep chasms carved by meteors are not in any way connected to the tectonic activity.
