sting8
In this question, "organic vegetables" are compared with "regular agricultural produce".
As per the OA, conjugate verb is "is", not "are"
So, the produce is singular subject.
My query is, can we compare plural subject ("vegetables") with singular subject("produce") ?
Moreover, I had read, when we are backed to 2 sentences with no significant errors, we should go ahead with concision.
Thus, should D not be better than A ?
There's no issue here with the singular/plural comparison. "For the restaurant, meat is more expensive than vegetables", or "Taxes are a less important issue than environmental policy" are both perfectly fine sentences, even though they compare plural things and singular things in one order or the other. These comparisons are fine, as is the comparison in the original sentence atop this thread, because you can think of "produce" or "meat" as plural things (mass nouns), and "taxes" as a singular thing. It would be very strange to say this, however: "Apples taste better than an orange", since there is no good reason to compare the plural with the singular -- "Apples taste better than oranges" makes a lot more sense.
The "Official Explanation" to this question is wrong when it says answer A is "stylistically sound" and D is not. It's much more natural in English to say "Organic vegetables are healthier than regular produce" than it is to say "Organic vegetables are healthier than regular produce is". There is no stylistic reason to add a superfluous "is" at the end of this sentence. We do sometimes need to insert a verb in comparisons like this when it would otherwise be unclear what is being compared. But there's no ambiguity in this sentence that we need an extra verb to resolve.
There is a stylistic problem with this sentence, but no answer choice solves it. When the sentence switches from an adjective phrase ("free of chemicals") to a comparison ("healthier than") it needs to restate the verb:
Organic vegetables are free of chemicals and are healthier than regular agricultural produce.This doesn't seem optional to me, when I think of similar sentences -- if the verb isn't restated, it becomes unclear what goes with what. So I don't think any answer choice here is correct, but D is the closest.
Lastly, about concision, I agree with you that all other things being equal, you should prefer the more concise answer. But it's important not to take that principle too far; on the GMAT, precision is much more important than concision. We often need to insert extra words in a sentence to make sure meaning is clear and unambiguous. Concision is rarely a decisive issue in GMAT SC -- there will usually be a better reason to favour one answer over the rest. Some people do take that concision principle too far, and use it as a basis for a guessing strategy. In some books, you might see the advice "if you have to guess quickly at SC, guess the shortest answer." I did a study of several hundred official SC questions a few years ago and worked out how often the shortest answer was the right answer. If answer choice length was completely unrelated to correctness, you'd expect the shortest answer to be right 20% of the time. It turned out the shortest answer was right 23% of the time, which is well within the margin of error, so I found no evidence the shortest answer was right more often than a random answer. That 23% might sound like it's giving you a very slight advantage, but when I subdivided the questions by difficulty level, it turned out on hard questions, which are the questions people are most likely to need to guess at, the shortest answer was right far less than 20% of the time. I wouldn't read anything into that, because the sample size isn't large when I look only at a subset of the questions. The only conclusion I can draw from looking at a lot of official questions is that there's simply no meaningful relationship between answer choice length and the probability an answer choice is correct. Guessing the shortest answer is no better than guessing a random answer, and it is in fact worse if you waste any time looking for the shortest answer.