Comparing Hypotheses on Light Intensity Effect on Fern Growth

In a recent study on plant growth, two hypotheses were proposed regarding the effect of light intensity on the growth rate of a particular species of fern. Hypothesis A states that increasing light intensity will significantly enhance the growth rate of the fern. Hypothesis B, on the other hand, posits that after a certain point, increasing light intensity will have no additional positive impact on growth and may even be detrimental. Researchers conducted an experiment with three groups of ferns, each exposed to low, medium, and high light intensities, to test these hypotheses.

Based on these hypotheses, what conclusion can be drawn about the relative effects of light intensity on fern growth?