This sentence is a metaphor. Metaphors are rhetorical figures of speech which have to do with symbolic comparisons without the use of comparing words such as <em>like </em>or <em>as </em>(because when those words are used, it is a simile). So here, the man is compared to a machine based on how many hours he can work. It is also not an analogy, because analogies are references to people or events outside of the work where the analogy is used.
<span>Buck knows the team cannot depend on these people for they do their work inefficiently and crudely. They are barely traveling ten miles a day, and it is inevitable they will run short on dog food. When this occurs, underfeeding commences. One by one dogs are dying, first Dub whose injured shoulder grows worse and worse, than almost all of the new dogs. The men curse, and Mercedes cries. They lack patience and constantly argue with one another. Charles and Hal constantly fight over who does more work, Mercedes flightily changing her allegiance from husband to brother and back again. All too often the three began to quarrel before the camp was pitched, and it would remain unpitched until the quarrel had ended.</span>
I think the correct answer is "D". Comparative adjectives compare one person or thing with another and enable us to say whether the person or thing has more or less of a particular quality. Example: "Ashley is shorter than Sally"
I’m not sure the context to this question, but not everyone had synesthesia so my guess is the answer is C, understand synesthesia.