The correct answer is A. The amount of sugar
Step-by-step explanation:
In experiments variables or factors that can be measured are often classified as dependent or independent. In this way, dependent variables include the main factor or factors that are being studied while the independent variable is the factor controlled by the scientists and therefore the factor that is believed affects the dependent variable. This means, in the case presented, the amount of sugar is the independent variable as this is the factor the student is manipulating to prove if it influences the mass of chemicals.