If we assume that the population of the town is proportional to the random people selected to take the survey, then we can say that the answer is A, People at least 50 years old are the largest age group in town. Since the survey is random and the percentage of the 50-year old population group is higher when individually compared to the other groups, we can assume that the town's population consists of a high number of people who are 50-years old or older.
And although it is not a given answer choice, it would actually make more sense to say that out of the number of people that took the survey, those who were 50 years old or older consisted of the largest age group.
