The conclusion is related to increase in profits, so eliminate options A, C & E since they do not talk about profits.

A - Incorrect, since profit is not being considered here.
B - Incorrect, since this option is somewhat in favour of the argument.
C - Incorrect, since profit is not being considered here.
D - Correct answer, because customers will sit for a short time, hence order less expensive meals, hence decrease/no increase in profits.
E - Incorrect, since profit is not being considered here.

The correct answer is D

This is a GMATPrep question. I have seen the screen shot and I can confirm that the
OA is C.

Since this is a GMATPrep question let's look at it in depth to see what can be learned.

First, we have a weaken question here. We want to criticize the conclusion that Hollywood restaurant would increase its profits with taller stools.

The reason given for these improved profits is that diners seated on stools typically do not stay as long.

We need something that indicates that EVEN THOUGH diners typically do not stay as long at high stools compared to regular tables, yet the conclusion that Hollywood would make more money MAY NOT BE TRUE.

Choice C gives us such a reason. Although typically a restaurant can get more diners per hour at these tall tables - since diners do not stay as long - this case is not typical. Diners are there to see celebrities and if they get one of these tall tables they may stay for hours. This is a strong choice.

Choice D is really the opposite. Choice D is assuming that the Hollywood restaurant follows the typical pattern and that people do not stay very long at the tall tables. Yet, would the restaurant not still benefit from serving several less expensive meals in the time that they might serve just one more expensive meal? This really does not weaken the idea that the Hollywood would make more profit with the tall tables.

Does that help?

Sorry!
Couldn't understand your explanation!
I choose "D" too!
Why "C"?

I also chose D.

David:
in your explanation for 'C' how can we safely assume that the cost for multiple low priced meals could be the same as one high priced meal?

At present the Hollywood Restaurant has only standard-height tables. However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities. Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables. Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.

The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available.
(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals.
(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering
(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer
(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating,re would be no view except of other tall tables.

This arguments exhibits a SCOPE SHIFT.
The premise is a generalization: diners seated at stools TYPICALLY do not stay as long.
The conclusion is about a specific situation: if the HOLLYWOOD replaced some of its seating with stools, the restaurant would increase its profits.

The passage links what diners TYPICALLY do to what diners at the HOLLYWOOD would do.
This connection is valid only if the diners at the HOLLYWOOD are TYPICAL.
To break the link, the correct answer will show that the diners at the Hollywood are NOT typical.

Answer choice C: a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering.
Answer choice C states that the diners at the Hollywood are an EXCEPTION: that sitting at taller tables will NOT induce them to stay for less time. And the passage offers the likely reason: many customers come to watch the celebrities. Since the stools would afford a BETTER view of the celebrities, the customers would likely stay LONGER.

Some test-takers will be attracted to answer choice D. Since we have no idea how much profit -- if any -- is derived from meals served at the Hollywood, the selling price of the meals is irrelevant. For all we know, most of the profits at the Hollywood come from selling BEVERAGES, not meals.