Independent variable question i'm not getting

[victorhugo]

I know that D is definitely a dependent variable, but I don't see how the others are dependent on anything else... The correct answer is A btw.
Please explain to me how B and C are dependent variables considering the investigation is to "determine and compare the heat of combustion of three different liquid alkanols."

 

[mfb]

A is the independent variable you want to study. B and C are free parameters in your experiment but they do not (or should not) influence the result.

 

[Zypheros_Knight]

Both B and C point to the same direction but we want to find the heat energy in Kj/mol of the alkanols...changing the amount of water to be heated would mean we would need change the amount of of the fuel this shows that the two variables are dependent on each other.If you want further clarification just ask.