Context: The passage below describes an experiment.

Mia grew roses for a flower shop. One day, she noticed tumor-like growths on her rose stems. She could tell that the plants had crown gall disease, which is caused by a type of bacteria. She knew that allicin, a chemical in garlic, can kill bacteria. Mia wondered if spraying her plants with garlic juice would prevent more tumors from forming on her plants.
Once a day, Mia sprayed garlic juice on ten infected plants and left another 10 infected plants unsprayed. After one month, she compared the number of new tumors on plants in the two groups.
Figure: crown gall tumors on a rose stem.
In this experiment, which were part of a control group?
A. the roses that were not sprayed
B. the roses sprayed with garlic juice
Identify the correct option from the choices provided and respond with the letter of the correct option.

A