Read the Following Scenario and Answer the Question Below

Multiple Choice

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 independent variable in this study will be ______________

A) the breed of the dogs
B) the sex of the dogs
C) the age of the dogs
D) how much the dogs grow
E) the type of food the dogs receive