You could use a scale to measure the mass as well as a cup to hold the water. If you were comparing the two, you should also probably use a graduated cylinder to get the same amount of each type of water.
Hope this helped ^_^
Im just guessing, so i think is A
From the given equations, the combustion reaction is;
C₄H₁₂ + 7O₂ --> 4CO₂ + 6H₂O
Combustion reactions are when organic compounds react with O₂ to produce water and CO₂. From the given reactions, C₄H₁₂ is an organic compound that reacts with O₂ to produce water and CO₂.
Therefore this is the only reaction that follows the general equation for combustion.
