Answer: B) What you keep the same
A controlled variable is what is held constant. When doing an experiment, it is ideal to only focus on one variable at a time while keeping everything else in check. This way you can compare two items effectively.
In contrast, a manipulated variable is one that is intentionally changed to see how it affects the subject. For example, if you're testing various fertilizers, then the fertilizer brand would be the manipulated variable. The soil, moisture, amount of sunlight, and other environmental factors are kept the same (each subject gets the same about of each) making them to be controlled variables.