What Is the Primary Reason That a Hot Spring Will

What is the primary reason that a hot spring will kill a fish placed in it,but encourage the growth of certain bacteria?

A) Fish cannot feed directly on bacteria,but the bacteria can feed on dead fish.
B) Bacterial growth at high temperatures is so rapid that it deoxygenates the water and kills the fish.
C) At hot spring temperatures,the metabolic activity of the fish's cells is so rapid that it runs out of food reserves and dies; the bacteria feed on the dead fish.
D) The high temperatures denature most of the fish's enzymes,but the specialized bacteria have enzymes adapted to these temperatures.