How does an island become a seamount?

Seamounts form by submarine volcanism. After repeated eruptions, the volcano builds upwards into shallower water. If a seamount eventually breaches the water's surface, it becomes an island. ... They may form in groups or clusters, or can be found aligned in submarine volcanic mountain chains known as oceanic ridges.

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser 

None   they are   equally likely to occur on any plate boundary