When tested on the Binet-Simon scale, Ada is found to have a mental age of eight. This means

A) that she is intellectually impaired.
B) that her performance was as good as that of an average eight-year-old child.
C) that her score is eight standard deviation units above the average score.
D) that her IQ is 80.

A mental age of eight on the Binet-Simon scale means that Ada's performance was as good as that of an average eight-year-old child. It does not necessarily mean that she is intellectually impaired or that her IQ is 80 (which would depend on the specific IQ test used and its scoring system). Additionally, the option about eight standard deviation units above the average score is not relevant, as the Binet-Simon scale does not use standard deviation units.