Use the Following Figure to Answer the Question

Use the following figure to answer the question.

Based on the figure, which of the following are plausible reasons for the results?
I.Nutrients in the control watershed are being lost due to evapotranspiration from leaves.
II.Nutrients dissolve in the water running through the watershed.
III.Nutrients are attached to small particles of sand or clay that leave the watershed.
IV.Intact vegetation includes plant roots that held soil particles and prevented nutrient loss.

A) only I and III
B) only II and IV
C) I, II, III, and IV
D) only II, III, and IV