The correct answer is I, II, and III.
All three options can cause tsunamis:
- I. Earthquakes: Most tsunamis are caused by underwater earthquakes.
- II. Volcanic eruptions: Explosive volcanic eruptions can displace large amounts of water, generating tsunamis.
- III. Landslides: Both underwater and terrestrial landslides can also lead to tsunamis if they displace enough water.
Therefore, the answer is I, II, and III.