100
                            These are the only two planets in our solar system without moons...
A: Mercury & Venus, 
B: Venus & Mars, 
C: Uranus & Neptune, 
D: Neptune & Pluto
                            What is A: Mercury & Venus.  As far as we know, Saturn has the most moons.  Saturn has at least 25 satellites that measure at least 6 miles (10 kilometers) in diameter, and several smaller satellites. The largest of Saturn's satellites, Titan, has a diameter of about 3,200 miles (5,150 kilometers) -- larger than the planets Mercury and Pluto.