All three of the options you provided can cause tsunamis:
I. Earthquakes - Most tsunamis are triggered by underwater earthquakes, especially those that occur along tectonic plate boundaries.
II. Volcanic eruptions - Volcanic eruptions, particularly explosive eruptions or eruptions that cause land or volcanic islands to collapse into the sea, can generate tsunamis.
III. Landslides - Landslides, whether they occur underwater or when large amounts of debris fall into the ocean, can also displace water and create tsunamis.
So, the answer is that all three can cause tsunamis.