Answer :
Final answer:
A 9-year-old who responds to the original Stanford-Binet IQ test with the proficiency of an average 12-year-old would have an IQ of 115.
Explanation:
The original Stanford-Binet IQ test is designed to measure a person's intelligence compared to their age group. If a 9-year-old responds to the test with the proficiency of an average 12-year-old, it means that their intellectual abilities are more advanced than their peers. In terms of IQ, this would be considered above average. The correct answer to the question is b. 115.
