The 3rd one is your correct answer. :3
A low pitch sound example would be like a crocodile. They can produce sound so low for the human ear to hear. Thunder can also produce exceptionally low pitched sounds that are felt much as they are heard.
The last one. They can't go on and they can't stay where they are. They've got to be on their home asteroid in two weeks which we are to think that there is not enough time to go to earth to get a cruiser and return home in that. Nor can they stay where they are. They know that the miners have taken every ship available. They're caught in a net and there doesn't seem to be any solution.
One is just a statement of the way one of the characters looked. It is a quick observation about the way he looked. "Lean and Hungry" is another way to describe him. If there was a way of getting a ship, the way he looks tells us that he would have found a way.
Two is just a fact that is part of the setting. He's at the biggest port on Mars. Nothing there. How the 2 characters feel about that is more important than where they were. We just have to know that if there is nothing in that city, there's going to be nothing anywhere else on Mars.
Three is close, but four is better because it is more emotional. The second best answer is Three.
