The number of new cases occurring in a defined population during a specific period of time is known as:

Correct option is C

Incidence refers to the number of new cases of a disease or condition that develop in a specified population during a defined time period. It is a measure of risk and is useful for identifying the onset of disease and evaluating the effectiveness of preventive interventions. Incidence is a dynamic measure and is usually expressed as a rate per 1,000 or 100,000 people.
Explanation of options: (a) Point prevalence – This measures the total number of existing cases (both new and old) at a specific point in time. (b) Period prevalence – This includes all cases (new and existing) that occur over a defined time period, not just new ones. (c) Incidence – This is the correct answer. It specifically focuses on new cases over a period, making it ideal for tracking disease emergence. (d) Rate – This is a general term used in epidemiology; incidence rate is a specific type of rate, but rate alone lacks specificity.