A nurse is teaching the parent of a 2-year-old toddler about increased risks of middle ear infection. Which statement by the parent indicates understanding of the teaching?

A. "Toddlers have fully developed immune systems.": Toddlers have immature immune systems, particularly in producing antibodies against certain pathogens, which increases susceptibility to infections, including otitis media. Believing their immune system is fully mature reflects misunderstanding of infection risk factors. B. "My child produces more cerumen than older children.": Cerumen production is not significantly higher in toddlers compared with older children, and excessive wax alone is not a major risk factor for middle ear infections. Infection risk is more closely related to anatomy and Eustachian tube function. C. "The tympanic membrane is thicker in toddlers.": The tympanic membrane in toddlers is not thicker than in adults; in fact, it is thinner and more susceptible to inflammation and infection. This does not contribute significantly to the increased risk of otitis media. D. "My child's Eustachian tubes are shorter and more horizontal than an adult's.": The horizontal and shorter anatomy of toddlers’ Eustachian tubes facilitates the reflux of nasopharyngeal secretions into the middle ear. This anatomical characteristic, combined with immature immunity, increases the risk of fluid accumulation and bacterial growth.