The Age Before Which Symptoms Must Be Evident in Order

Multiple Choice

The age before which symptoms must be evident in order to substantiate a diagnosis of intellectual disability is

A) fairly arbitrary.
B) based on medical considerations.
C) based on the significant differences found in individuals who are either just above or just below the designated age.
D) based on studies showing that the designated level separates most individuals with brain deficits from those who do not have such abnormalities.