You are growing plants for the science fair. You have planted 100 marigolds. All have been planted in the same size planter with the same type and amount of soll. 50 will be put in the dark and talked to everyday. The other 50 will be put in the sun but ignored. You want to know if the communication helped the plants in the dark to grow even though they lacked sunlight. Which of the following variables is the control in the given scenario?
a) The soil
b) The sunlight
c) The communication
d) The darkness