A Landscaping Firm Has Been Hired to Replant a Hillside

A landscaping firm has been hired to replant a hillside whose vegetation (primarily elm trees) has been decimated by an outbreak of Dutch elm disease.The landscapers decide to introduce new elm trees that have been engineered to contain a fungicide (a chemical toxic to organisms containing chitin) .Despite their best efforts, these new trees fail to thrive after planting.What is the most likely explanation for their failure to grow?

A) The fungicide is damaging the tree's roots, resulting in stunted growth.
B) The fungal partners necessary to form mycorrhizal associations are not present in the soil.
C) The fungicide has killed the endophytic fungi that usually protect the leaves from other pathogens, resulting in an increase in disease.
D) The hillside environment is not ideal for the growth of elm trees.
E) The fungicide is toxic to the fungi that normally form mycorrhizal associations with the tree's roots, thereby reducing nutrient availability for the plant.