In a scenario where Gary's Gym and eFitness reach a Nash equilibrium, which of the following best explains why neither firm would want to change their strategy?

In a Nash equilibrium, both Gary's Gym and eFitness have chosen their best strategies given what the other firm is doing. This means that neither gym can improve its situation by changing its strategy alone. For example, if Gary's Gym offers a lower price for memberships and eFitness matches that price, both gyms find themselves in a stable position where neither can attract more customers by changing their prices. If either gym tried to change its strategy, like raising prices, it could lose customers to the other gym, which would not be beneficial. Therefore, in this situation, both gyms stick to their strategies because any change would likely lead to a worse outcome for them.