After the Galileo spacecraft reached Jupiter, it dropped a probe on a parachute into Jupiter's atmosphere, which is mostly hydrogen. As this probe descended deeper and deeper into Jupiter's interior, what would it have encountered?
(a) The atmospheric pressure would have gradually increased until the probe splashed onto the surface of an immense, liquid-hydrogen ocean.
(b) The probe would have fallen through a deep, gaseous atmosphere of greatly increasing pressure until it finally landed on the surface of a hard, rocky core.
(c) The atmospheric gases would have become denser and denser until they were dense enough to be called a liquid, without any distinct boundary or "surface" at all.
(d) Jupiter is entirely a gas, and the probe would have fallen to the center of the planet, where it remains today.