Final answer:
Most of Venus's early water would have been found in oceans before a runaway greenhouse effect caused its permanent loss.
Step-by-step explanation:
The question asks where most of Venus's early water would have been found. Historically, Venus may once have had a climate similar to that of Earth, with moderate temperatures and water oceans. However, due to a runaway greenhouse effect, Venus experienced a permanent loss of water. The additional heat from the Sun caused increased evaporation of water from the oceans and the release of gases from surface rocks, hence most of Venus's early water would have likely been found in Oceans (Option B) before these processes led to its evaporation and the irreversible loss of water.