The answer is "B" - If there are no windows then there will be no light coming in, and therefore you don't have to worry about what time of day you do the experiment at.
Answer: Jupiter's mass
Explanation:
From Kepler's third law:

where T is the orbital period of a satellite, a is the average distance of the satellite from the Planet, M is the mass of the planet, G is the gravitational constant.
If the average distance of one of Jupiter's moons to Jupiter and its orbital period around Jupiter is given then mass of the Jupiter can be found:

The name of the scientist who incorrectly theorized that it was the positive charge that moved through a circuit is Benjamin Franklin. Franklin made his famous experiments with a kite in a charged cloud.
He was the scientist that made the electrical notation where the current is given by the direction of the positive charges flow.