Based on Its Surface Features, the Most Important Event on Venus

Based on its surface features, the most important event on Venus in the past billion years or so was .

A) a global "repaving" that erased essentially all the surface features that had existed earlier
B) the impact of an unusually large asteroid that left a deep scar on one side of the planet
C) the eruption of a giant volcano that formed one of Venus's "continents"
D) the onset of mantle convection, which caused Venus's lithosphere to split into plates like those on Earth