Some Astronomers Suspect That Saturn's Satellite Enceladus Could Be Heated

Some astronomers suspect that Saturn's satellite Enceladus could be heated enough by tidal flexing to produce active geysers of water on its surface, in a mechanism similar to that operating on Jupiter's satellite Io. Which one of the following statements is a correct observational fact supporting this conjecture?

A) A strong electric current flows from Enceladus to Saturn along Saturn's magnetic lines of force.
B) Enceladus is a "shepherd satellite" for the braided F ring, which could be made up of ice particles from the geysers.
C) Active volcanoes were photographed on Enceladus by the Voyager spacecraft.
D) Enceladus orbits inside the faint E ring, which may be made up of ice particles from the geysers.