You May Be Aware of a Fungal Pathogen Known as Dutch

You may be aware of a fungal pathogen known as Dutch elm disease. This disease is transferred via a vector-the elm bark beetle. Damage to the plant actually results from the plant's attempts to limit the fungal growth. The plant typically forms a plug in its xylem so that the fungal growth cannot receive the necessary water and minerals. This causes damage to the tree from the top down. Currently, there are three methods of treatment for this disease. Below is list of the three methods and the numbers of trees per thousand that survived after treatment: Treatment A = removing limbs that show signs of disease; 350/1000 survived Treatment B = use of a fungicide; 700/1000 survived Treatment C = another fungus is injected into the tree to boost immunity; 500/1000 survived From this study, which treatment appears to be the most effective against Dutch elm disease?

A) treatment A
B) treatment B
C) treatment C
D) They are all totally ineffective.