Answer:
For your first question it's C) the galaxies are moving closer together as time progresses.
You see the universe is expanding because of dark energy, which entails each galaxy is moving further and further away from the other galaxies in the universe.
For your second one, it's A) Energy that humans can't directly observe.
Dark energy, as well as dark matter are called "dark", not because it has to do with the dark force in star wars... no. it's because we can't directly observe what it is. However we can observe its affects.
