Some Types of Pine Trees Are Attacked and Fed on by Pine

Some types of pine trees are attacked and fed on by pine bark beetles.As the beetles feed, they girdle the trees, destroying the phloem layer and killing the trees.Pine bark beetles are also associated with the blue stain fungus, which grows in their frass (feces) .As they attack the trees, the beetles also inject the fungus.The fungal hyphae grow into the tree and follow its xylem cells, blocking the flow of xylem and causing rapid tree death.Suppose pine bark beetles that lacked the blue stain fungus attacked pine trees.How would the absence of the blue stain fungus be likely to affect the death rate of pines?

A) There would be little effect; the beetles would still kill the trees.
B) It would be lower; only beetles, not fungus, would be killing the trees.
C) It would be higher; beetles would be more efficient without the fungus.
D) It would be high but slower; only beetles, not fungus, would be killing the trees.
E) It would be high but faster; beetles would be more efficient without the fungus.