Chandra is doing an experiment to find out which type of dog food her dog prefers. the following are the steps of her experiment:

1. place five identical bowls next to each other in the dog's yard.

2. place a different type of dog food into each bowl.

3. observe which foods the dog eats and how much of it he eats.

4. record all observations.

5. repeat the experiment at the same time every day for the next week.

6. analyze the results.

which variable did chandra change in the experiment?
a.
the type of dog food
b.
the dog food bowl
c.
the time of day the dog was fed
d.
the type of dog