In the experiment, students put brine shrimp in water with different concentration of salt and counted the number.Which of the following changes to the experiment will increase confidence in the validity of the result? a.        Count the number of dead brine shrimp instead of living brine shrimpb.        Add more brine shrimp to the water with the highest salt concentrationc.        Repeat the experiment several times, and calculate the average number of brine shrimpd.        Reduce the length of the experiment from 24 hours to 8 hours.