Please Use the Following Information to Answer the Questions Below

Multiple Choice

Please use the following information to answer the questions below.
A scientist conducts an experiment to quantify the effect of mycorrhizae and soil nitrogen levels on plant growth in a grassland.The experiment has four treatments: (1) mycorrhizae present and ambient levels of nitrogen, (2) mycorrhizae present and nitrogen added, (3) mycorrhizae absent and ambient levels of nitrogen,and (3) mycorrhizae absent and nitrogen added.After four weeks,the scientist removes the aboveground plant material for weighing.
Figure 42.4
-What conclusion is best supported by Figure 42.4?

A) With ambient nitrogen levels,growth is limited even when mycorrhizae are present.
B) Mycorrhizal associations result in the highest NPP levels regardless of nitrogen level.
C) Interactions with mycorrhizae are always positive mutualistic fungal-plant interactions.
D) Mycorrhizae should be added to restore successfully grasslands with high soil nitrogen.