The argument states that more gym memberships are bought in Schwartz than in Talsberg, and concludes that citizens of Schwartz exercise more frequently than citizens of Talsberg.
For each option, I'll determine whether it weakens the argument:
A) Schwartz has a larger population than Talsberg does.
This weakens the argument because if Schwartz has more people, it would naturally have more gym memberships even if its citizens don't exercise more frequently on a per-person basis. The raw number of memberships doesn't tell us about exercise frequency per citizen.
B) Most citizens of Talsberg work in Schwartz and have memberships in gyms there.
This weakens the argument because it explains that many of the gym memberships counted for Schwartz actually belong to Talsberg citizens, meaning Schwartz citizens aren't necessarily exercising more.
C) The average price of a gym membership is lower in Schwartz than it is in Talsberg.
This does NOT weaken the argument. Lower prices might explain why more memberships are purchased in Schwartz, but it doesn't challenge the conclusion that Schwartz citizens exercise more frequently. If anything, more affordable memberships could support higher exercise frequency.
D) A large, free community gym open to all is available to the citizens of Talsberg.
This weakens the argument because it suggests Talsberg citizens may exercise frequently at this free gym without needing paid memberships, so the membership count doesn't accurately reflect exercise frequency.
E) The average citizen of Schwartz spends less time at the gym per week than does the average citizen of Talsberg.
This directly weakens the argument by stating that Talsberg citizens actually spend more time exercising at gyms, contradicting the conclusion.
Since we're looking for the option that does NOT weaken the argument, the answer is C.