You Are Conducting an Experiment to Determine If Listening to Music

Multiple Choice

You are conducting an experiment to determine if listening to music improves learning.If there was no difference between the test performance of the experimental and control
Groups,then we can conclude that

A) extraneous variables were not controlled.
B) the two groups were not randomly assigned.
C) listening to music improved learning.
D) listening to music had no effect on learning.