To Construct a Series of Tuning Curves, Which of the Following

Multiple Choice

To construct a series of tuning curves, which of the following experimental conditions is required?

A) Several different tones must be evaluated.
B) Tones used must be pure.
C) A range of different intensities must be used.
D) At least one high- and low-frequency tone must be used.
E) Intensities must all be the same at a given frequency.