Use the Following to Answer Questions

Multiple Choice

Use the following to answer questions
Scenario I
A psychologist interested in studying visual perception manipulates the brightness of a light in the imperceptible to very dim range.Each level of brightness (measured in lumens) is studied for 10 trials,and on each trial participants are asked if they can detect the light.Figure 4.1 shows hypothetical data from one participant.
Figure 4.1
-(Scenario I) What the participants perceive as the brightness of the light is determined by the _____ of the light wave.

A) color
B) frequency
C) amplitude
D) purity