Which of the Following Was One of the Assumptions Made

Which of the following was one of the assumptions made by Alfred Binet in his research on intelligence?

A) The characteristics of highly intelligent and successful people are largely determined by heredity.
B) Chronological age is a better determinant of intelligence than is mental age.
C) The rate at which a person gains knowledge is largely determined by the environment.
D) The rate at which a person gains knowledge is an internal characteristic and remains relatively constant over time.