How Does the Geological Activity on Io Compare to the Activity

Multiple Choice

How does the geological activity on Io compare to the activity on other moons?

A) It is almost completely inactive.
B) It occurs at widely spaced intervals but is highly active when it does occur.
C) It is very active on a regular basis.
D) It used to be inactive but has slowly increased activity over the past few million years.
E) None of these is an accurate description of Io's geological activity.