Chronological age refers to the number of years a person has lived.

• A. Number of years lived.
• B. Level of education
• C. IQ score
• D. Age at death

Answer: (A)

Chronological age is the number of years since a person was born. It is a simple, time-based measure of how old someone currently is, independent of any health, education, or abilities. This matches the statement exactly because it defines age by the years lived since birth.

The other concepts describe different things: level of education reflects schooling completed, IQ score gauges cognitive ability, and age at death indicates the total years lived up to death rather than the current age.