Explanation

Reading the question: this prompt may be puzzling at first. However, regardless of whether we can think of an explanation easily, we can see that we have to "explain" in this question. That means that the correct answer will link to two pieces: 1) demand for wine has not increased, and 2) prices and production amounts are stable, but profits are up. The "except" indicates that four answer choices will explain this, and one will fail to explain it.

Creating a filter: we already have a filter, which is linking to points 1) and 2) that we've just identified. Further, we can briefly imagine some broad possibilities. Some other costs may have gone down; taxes could have been erased; maybe people switched from cheaper wines to more expensive wines (we're not sure whether this one is allowed by the information, but it does occur to me). Broadly, we want to increase profits and/or decrease costs, without challenging the information given.

Applying the filter: We dislike (A), so we skip it. This is an EXCEPT question, so we are keeping our filter basic and skipping anything that's not simple on the first pass. Choice (B) decreases a cost, so it's a good explanation, so it's not the answer. Same with choice (C): it's a valid explanation, so it's an invalid answer choice. Ditto for (D). Same for (E). Choices (B) through (E) all involve costs going down, so the correct answer must be (A). On further scrutiny, choice (A) just adds to the mystery, since the overall consumption of wine has decreased. It doesn't explain the mystery, so it's the correct answer. The correct answer is (A).