Hi Qiranz! Thanks for your question
Answer choice (C) actually mixes up the characteristics of the positive-displacement and centrifugal pumps! According to the passage, the positive-displacement pump's design pushes
fluid and the centrifugal pump's design sucks in
fluid. However, answer choice (C) states that the positive-displacement pump sucks in fluid, which is the opposite of what the passage states.
We can infer answer choice (E) is true from the passage because the passage tells us that the positive-displacement pump's design puts crude into contact with most parts of the pump, and that the centrifugal pump has a different design. Since the centrifugal pump has a different design and the passage states that the design of the positive-displacement pump is what puts crude into contact with most parts of the pump, we can infer that one difference between the two pumps is that the positive-displacement pump comes into contact with crude but the centrifugal pump does not.
I hope this helps, and let me know if you have any other questions!