From the options you listed, the most accurate answer is: How does the artist use light and dark tones?
The other options are not centered on the artwork but on the things surrounding it. By knowing how much money the artist gains, you can only figure out the monetary value but you can't tell anything from the artwork itself. By looking to the people's reaction, the same thing happens, they aren't able to give you enough information to interpret the artwork.
The question refering to the use of tones focuses on the artwork, in this way it is possible for it to tell you something or to give you information.
Some experts suggest some steps for interpreting artwork which involve: looking at it (the material or medium used and the appereance), seeing it (applying meaning to it) and thinking about it (in a creative way to figure out possible meanings).
