Geysers Periodically Boil and Erupt Because ________

Geysers periodically boil and erupt because ________.

A) new groundwater flows in to replace that lost in the prior eruption, this takes time
B) great pressures from deep water-filled chambers prevent water from boiling until higher temperatures are reached; eventually enough heat is supplied by the hot (volcanic) rocks to expand the water and let it boil anyway
C) each injection of hot magma at depth triggers another episode of boiling in groundwater
D) the god Vulcan is at work at his subterranean forge