Answer: D. This is not an experiment-there are no controls or replicates.
Step-by-step explanation:
An ideal experiment requires the environment for conducting the experiment, a control sample which is kept undisturbed and receives no treatment, an independent variable the effect of which is to be observed on the test samples or experimental variables.
In the given situation, the dependent variable is undefined, and there is no control sample is kept among the three materials given as a food source. The experiment is also not repeated to assure the results of the food materials on the puppy. Thus this can be said that the given situation is not an experiment.