Chinese‐food stalls make up 35 percent of all stalls in California. Visitors at these stalls tend to be young; in fact, studies have shown that the older people get, the less likely they are to eat at Chinese‐food stalls. Since the average age of the California population is gradually rising and will continue to do so, the number of Chinese‐food stalls is likely to decrease.

Which of the following, if true, most seriously weakens the argument?

(A) Chinese‐food stalls in California are getting bigger, so each one can serve more visitors. : Incorrect. Extra information and hence irrelevant.
(B) Some older people eat at Chinese‐food stalls more frequently than the average young person. : Incorrect. At least one older person eats at chinese stalls more frequently. the argument already states that the likelihood to eat chinese food decreases as a person gets older. So, even if one person eats at chinese food stalls more frequently, the conclusion that the number of Chinese‐food stalls is likely to decrease can still hold.
(C) Many people who rarely eat in Chinese‐food stalls nevertheless eat regularly in stalls. : Incorrect. Irrelevant.
(D) The overall population of California is growing steadily. : Correct. This weakens the conclusion. Because the overall population is growing, the number of young people is also growing. so, the number of chinese food stalls may not decrease.
(E) As the population of California gets older, more people are eating at home. Incorrect : Tells us nothing relevant.