Answer:
B. Group B only
Step-by-step explanation:
Control group is a research group that does not receive the substance being tested in the experiment. In the case shown in the question above, the experiment sought to test the effectiveness of a specific fertilizer in the growth of bean plants. For that, plants received the fertilizer (which is the tested substance) while plants did not receive the fertilizer (received only water), in this case, the plants that received only water are the control group of this experiment.