Whorfian tubules have an inside diameter equal to their length, a dens

Whorfian tubules have an inside diameter equal to their length, a density half that of water, and a mass that is immeasurably small. A physicist isolated an entity less dense than water, with insufficient mass to measure, and a length exactly equal to the diameter of its inside.

It would be certain that the physicist had isolated a Whorfian tubule if it were concluded by the physicist that

the physicist had been looking specifically for Whorfian tubules - irrelevant
Whorfian tubules are the only entities of immeasurably small mass with an inside diameter equal to their length - the reason for him not to consider the WT.
the density of what he had isolated was exactly half that of water - this is talking about only one component of the WT (B overpowers C)
Whorfian tubules are only found under the conditions that the physicist had duplicated - out of scope
Whorfian tubules were the only entities half the density of water with an immeasurably small mass - This is a lot closer to B for me.

Can anyone explain exactly why "E" is wrong.