Read the Following Scenario and Answer the Question Below

Read the following scenario and answer the question below.
Pablo and Johanna have to do a yearlong study for their biology course. After some discussion, they decide to try comparing their dogs and the diet that they feed them. Each has a dog from the pound, and both dogs are less than one year old. Pablo feeds his shepherd-mix dog a special diet of wet and dry foods from the local vet, while Johanna uses generic dry kibble from the supermarket for her bulldog. They want to see which diet results in bigger, healthier, faster -growing dogs.
-The reason the instructor gives them will include the fact that they have too many ______________

A) dependent variables and not enough independent variables
B) replicates and not enough variables
C) variables that they didnʹt control and not enough replicates
D) independent variables and not enough dependent variables
E) controlled variables and not enough uncontrolled variables