I need help! this is about "Bill Nye Energy Video" i'm trying to find answer. there 3 picture. please note small answer arent great answer. please finish atleast 1 and half!

great answer = brainlist

Jenny wants to test the electrical conductivity of two substances dissolved in water. she is preparing the containers for the experiment. which factor is most important for her to control? a) volumes of the solutions b) appearance of the solutions c) temperatures of the solutions d) concentrations of the solutions