A nurse is collecting data from a 2-year-old toddler who has AIDS. The nurse should inspect inside the toddler's mouth for which of the following opportunistic infections?

A. Koplik spots are small, white lesions on the buccal mucosa associated with measles, not HIV/AIDS. They are an early diagnostic sign of measles infection and do not indicate immunosuppression-related opportunistic infection. B. Gingivitis involves inflammation of the gums and can occur in healthy children or due to poor oral hygiene. While children with AIDS may have oral health issues, gingivitis is not considered an opportunistic infection directly caused by immune suppression. C. Oral candidiasis (thrush) is caused by Candida albicans, a fungus that can overgrow in immunocompromised individuals, such as a toddler with AIDS. It appears as white patches on the tongue, palate, or inner cheeks, and may cause pain, difficulty swallowing, or refusal to eat. Thrush is one of the most common opportunistic infections in pediatric AIDS patients. D. Canker sores (aphthous ulcers) are small, painful ulcers that occur in the general population due to minor injury or stress. They are not opportunistic infections and are not linked to immunodeficiency.