Trisha and Angeline want to do an experiment to see an expensive brand of mouse food is better for mice than a cheaper variety. They have twelve mice that they divide into "Group A" and "Group B." They decide to keep track of the following:
the weight of each mouse, including weight change and whether the mouse is overweight or underweight
the appearance of each mouse's fur: color, glossiness, smoothness, and greasiness
the apparent energy level of each mouse: lethargic, normal, hyperactive
How can Trisha and Angeline best avoid biasing their experiment?
A.
They should both make observations separately and not compare them until the experiment is over.

B.
They should choose the kind of food for each group of mice randomly each day and make sure they can't figure out which kind of food is which.

C.
They should clearly label which group of mice is getting which food so that they can compare the two groups throughout the entire experiment.

D.
The lab partner who is making and recording the observations should not know which group of mice is eating which food.