Over 100 years ago, French educational researchers Alfred Binet and Theodore Simon developed the first intelligence tests to identify children in need of remedial education. Binet and Simon developed their test to measure what Binet termed natural intelligence, or a natural ability to learn dissociated from the effects of educational instruction. Using Binet and Simon's intelligence test, each child's score could be compared with age-norms to arrive at the child's mental age. Shortly after this pioneering work, Louis Terman developed the intelligence quotient (IQ). There are two ways to calculate an IQ score. A ratio IQ is calculated by dividing person's mental age by their physical age and then multiplying the quotient by 100. A deviation IQ is calculated by dividing a person's test score by the average test score from their age group and multiplying this quotient by 100. Binet and Simon conceptualized natural intelligence in terms of learning:

a. achievement.
b. aptitude.
c. outcomes.
d. exertion.