Based on Everything We Have Learned About Venus and Mars,what

Based on everything we have learned about Venus and Mars,what is the most surprising aspect of Earth's climate history?

A) the fact that the temperature of our planet has remained relatively steady throughout our planet's history
B) the fact that Earth apparently got a lot of atmospheric gas from outgassing by volcanoes
C) the fact that Earth had enough water to form oceans
D) the fact that Earth's climate can be affected by changes in its axis tilt