Final answer:
The term that reflects the number of students affected with a secondary disability is comorbidity, as it denotes the presence of additional conditions alongside a primary one.
Step-by-step explanation:
The answer to the question of which term reflects the number of students affected with a secondary disability is c) Comorbidity. Comorbidity refers to the presence of one or more additional conditions often co-occurring with a primary condition. In contrast, Prevalence is a measure that reflects the total number of both new and existing cases of a disease in a population at a given time. Incidence refers to the number of new cases of a disease during a specific time period. A Pre-existing Condition is a medical condition that existed before someone's health benefits went into effect. In the context of secondary disabilities, comorbidity is therefore the correct term, as it captures the idea of students having an additional disability alongside their primary one.