Tsunamis can be caused by all three of the listed factors:
I. Earthquakes - One of the most common causes of tsunamis. Underwater earthquakes can displace a large volume of water, leading to tsunami waves.
II. Volcanic eruptions - Explosions from volcanic eruptions, especially those occurring underwater or near the coast, can also displace water and generate tsunamis.
III. Landslides - Landslides, whether they occur underwater or when sediment falls into the ocean from the shore, can displace water and trigger tsunamis.
Given this information, the correct response is: I, II, and III.