Objections to the "Stepping-Stone" Hypothesis, Suggesting That Deep-Sea Hydrothermal Vent

Objections to the "stepping-stone" hypothesis, suggesting that deep-sea hydrothermal vent organisms are dispersed by taking advantage of whale falls (like stepping-stones) , include all of the following except

A) the number of overlapping species found at multiple sites is small.
B) most whales live and die in shallow waters.
C) increasing numbers of vents found suggest that dispersal is not a problem.
D) chemosynthetic organisms found at whale falls are not the same as at hydrothermal vents.