Katherine wants to investigate if the time of day a plant is watered affects the growth of the plant. She waters diferent plant same amount of water at different times in the day. The plants are sitting in the same location and get the same amount of sunlight.

**Chose one right answer PLEASE**

Which variable is missing from the experiment?

A. Independent variable; plants should be watered at different times of the day

B. Controlled variable: experiment should use the same types of plants

C. Dependent variable; the amount of sunlight should change daily

D. Controlled variable: experiment should use the same amount of water​