The correct answer is A. will be the wavelength of the light
Step-by-step explanation:
In an experiment, there are two main variables: the independent variable and the dependent variable. In the case of the independent variable, this refers to the factor or element that is manipulated on purpose to understand the relation of the independent variable with the main phenomenon being studied (dependent variable).
This implies, in the experiment presented the independent variable will be the wavelength of the light because this is the factor or variable that is being manipulated. On the other hand, the dependent variable would be the rate of photosynthesis because this is the element studied that is affected by the independent variable.