An independent variable refers to the variable, which is controlled or changed in a scientific examination to test the influences on the dependent variable. A dependent variable refers to the variable being tested and determined in a scientific experiment. A control variable is the one factor, which is not modified all through an experiment.
In the given case, the second rabbit, B would be the control as it does not receive the special treatment. Rabbits being shaved is the independent variable, the color it turns is the dependent variable.