After Reading the Paragraph Below, Answer the Question That Follows

Multiple Choice

After reading the paragraph below, answer the question that follows.
Over a period of just fifteen years ending in 2006, the mountain pine beetle has killed an estimated twenty millions acres of trees in the Rocky Mountains of British Columbia. These dead trees, in addition to no longer photosynthesizing to remove CO₂ from the atmosphere, will actually emit it during their decomposition. As of 2013, the mountain pine beetle has since killed about 50% of the total volume of commercial lodgepole pine in BC.
-The beetles, and a fungus with which they are often infected, together damage the xylem cells, which causes

A) an inhibition of photosynthesis.
B) a disruption of the Calvin cycle.
C) a blockage of water transport.
D) an inhibition of respiration.