Final answer:
Io, the innermost of Jupiter's Galilean moons, experienced an episode of tidal heating, making it the most volcanically active body in the solar system.
Step-by-step explanation:
The moon that underwent an episode of tidal heating in the past is Io, the innermost of the Galilean moons of Jupiter. Unlike Earth's Moon, Io is highly volcanically active due to the intense tidal heating it experiences from Jupiter's massive gravity. This heating causes Io's shape to distort, creating friction and heat within its interior, leading to extensive volcanic activity. Europa, while also experiencing tidal forces, is primarily known for its subsurface ocean, but it is Io that holds the title for the most volcanically active body in our solar system due to its proximity to Jupiter and resultant tidal heating.