Hi, avenging,
This is a difficult question, so don't stress about having trouble with it!
Expansion questions have two roles
- 1) Extrapolate on the immediately preceding content
2) Test your understanding of the main idea
You are correct to refer to the previous paragraph, but your work does not stop there. You must remind yourself what the main idea or primary purpose of the passage was, in this case that doctors are actually professionals because their "profession" involves some commitment to an ideal rather than just a handicraft.
Now consider what was discussed in the final paragraph:
- What it means to be a professional
Since we now have a complete description of what it means to be a professional, relate this concept back to the main point: "Doctors are professionals because they work for the common good."
To follow this last paragraph, your prephrase could be that you are looking for something that establishes a relationship between doctors (the topic of this passage) and this description of professionals. You need to return to the main point of the passage.
Hypothetically, you could follow the last paragraph with something that emphasizes how physicians embody all the ideals enumerated in the last paragraph, but the LSAT chooses a different route: instead, a critic's viewpoint is offered. Notice the implicit and expected disagreement after answer choice B. Answer choice B is the only answer that relates back both to the preceding paragraph and the main point of the passage, so it is the credited response.