A researcher wants to test how diets A and B affect the weight loss of rabbits. She has 20 rabbits to use, but all of the rabbits are different sizes, which might affect how much weight they lose. The researcher decides to group the four smallest rabbits in one group, the next four smallest rabbits in another group, etc., until the final group has the four largest rabbits. Then, from each group she randomly selects two rabbits to have diet A, and the remaining rabbits in the groups have diet B. Select all that apply. Select one or more: This is an example of a block design.This is an example of a completely randomized experimentThis is an example of a matched pairs experiment.The treatments are diets A and B.The treatment is how much weight a rabbit loses.The experimental units are the 20 rabbits.The experimental units are diets A and B.