The number of cases of a disease, injury, or disability at a given point of time, which can be expressed as the number of new cases or the number of existing cases, is called:

Correct option is B

Prevalence refers to the total number of cases of a disease, injury, or disability in a population at a specific point in time or over a defined period. It includes both new and existing cases. Morbidity and incidence are part of this 

• Morbidity (Option 3) refers to the state of being diseased or the presence of disease in a population, but it does not necessarily refer to the count of cases at a specific time.

• Incidence (Option 4) refers to the number of new cases of a disease or condition in a specific time period, not the total number of existing or new cases at a given point in time.