Which of the following is a common risk factor for otitis media in children?

A. Living in a warm climate is not a recognized risk factor for otitis media. Seasonal variations (cold/flu season) may play a role, but climate alone is not a cause. B. Being breastfed actually protects against otitis media because breast milk provides maternal antibodies and helps strengthen the immune system. C. Exposure to secondhand smoke is one of the most common and well-documented risk factors for otitis media. Smoke irritates the respiratory tract and Eustachian tubes, leading to inflammation, fluid retention, and increased susceptibility to infection. D. Drinking too much milk does not directly cause otitis media, though bottle-feeding (especially when lying flat) can increase the risk by allowing fluid to enter the middle ear.