Why Was It Thought That Titan May Have Oceans of Methane

Why was it thought that Titan may have oceans of methane?

A) Titan's atmosphere contains traces of methane. Similarly, Earth's atmosphere contains traces of water vapor. So, scientist thought Titan should have methane oceans.
B) The atmospheric pressure at Titan's surface and its surface temperature are such that methane should be liquid on Titan's surface.
C) The abundance of hydrocarbons in the atmosphere of Titan, led scientists to believe that Titan had an abundance of methane on its surface.
D) Titan's atmosphere is like Earth's (mostly nitrogen) , but its temperature is too low for water to be in the liquid phase. The only other possible liquid was methane.
E) Since Saturn has methane ice in its atmosphere, methane should be abundant in this region of the solar system. The sheer abundance of methane in the region led scientists to hypothesize methane oceans on Titan.