The incorrect option would be c. Insect stings occur most often during the spring and summer months.
Insect stings can occur at any time of the year, not just in the spring and summer months. In some regions, certain insects may be more active in the spring and summer months, but this is not universally true for all insects. Stings can occur any time of the year depending on the climate, region, and time of day. Additionally, the seasonality of sting occurrences may vary from region to region, making it not accurate to say that insect stings most often occur in the spring and summer months.