Answer:
The plant D represents the control group
Explanation:
In a scientific experiment, a control group can be described as the group in which no changes are made. The experimental groups are the ones in which changes are made and the experimental groups are compared with the control group to study the effects of the changes which occur in the experimental groups.
In the following scenario, the plant D is the control group as it is not listening to any kind of music. The growth of the other plants will be compared to this plant.