In the case of Rota meter, which is used for measuring the water flow rate?

• A. Only one variable is involved, i.e. independent variable ( the Rota meter reading)
• B. Only two variables are involved: one independent variable( the Rota meter reading) and one dependent variable (the water flow rate)
• C. Only two variables are involved: one independent variable(the water flow rate) and one dependent variable (the Rota meter reading)
• D. Only one variable is involved, i.e. independent variable ( the water flow rate)