Is it D
as it is asking about inference
The passages main concern is increasing health care costs and option D does address it..
Whereas if we look at other options
A is just re stating the premise stated in the argument above..its not an inference
B out of scope ..we arnt concerned about advantages and disadvantages
C again is re stating the premise
E is opposite of what is mentioned in premise

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Disagree, "D" is too strong as it confines the reason for a medicine costs spike to eldelry people. Stimulus of the passage doesn't bring up anything similar to it.
"C" is not a restatement, it's an inference itself as nothing is mentioned in the stimulus that higher medicine costs is a consequence of more people to agree on surgery due to high efficiency and lower costs.

A very good question to train pre-thinking skills, as "C" is the 1st option that comes to mind while reading.

(A) Ten years ago, few people had successful cataract surgery. No comparison given hence INCORRECT

(B) In the long run, the advantages of advanced medical technology are likely to be outweighed by the
disadvantages.INCORRECT

(C) The total amount spent on cataract surgery has increased because the increased number of people electing to have
the surgery more than offsets the decrease in cost per operation. CORRECT

(D) Huge increases in the nation's health care costs are due primarily to increased demand for surgery for older
people.INCORRECT

(E) Ten years ago, cataract surgery was affordable for more people than it was last year. INCORRECT

Premises:
- Nation's health care costs are going up due to high tech medicine
- e.g. the cataract surgery is cheaper and more effective
- So more operations are getting done and total cost is increasing

So cataract surgery is getting cheaper but total cost is increasing because many more operations are getting done.

(A) Ten years ago, few people had successful cataract surgery.
Cannot infer. The argument only says that it was "not always effective". That doesn't tell us anything about the success rate. We just know that it was not 100%. Few implies a very low success rate. That we cannot say.

(B) In the long run, the advantages of advanced medical technology are likely to be outweighed by the disadvantages.
Irrelevant to the argument

(C) The total amount spent on cataract surgery has increased because the increased number of people electing to have the surgery more than
offsets the decrease in cost per operation.
Certainly makes sense. The total amount increased because more people got the surgery done. So the increase in number of people offset the decreased cost.
Say 10 yrs back 10 people used to get it done and cost was $100. So total cost was $1000.
Now the total cost has gone up to 1500 though the surgery cost has gone down to $50. Then it means that 300 people are getting it done. So increase in number of people is offsetting the reduced cost.

(D) Huge increases in the nation's health care costs are due primarily to increased demand for surgery for older people.
We are not given this. The author talks about increased health care costs due to better technology and then illustrates how using cataract example (which is a surgery usually for older people). He does not say that the increased health care costs are PRIMARILY due to surgery for older people. Cataract is just one example of how better technology is increasing health care costs.

(E) Ten years ago, cataract surgery was affordable for more people than it was last year.
No. Cataract surgery has become more affordable now than it was.

Answer (C)
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