(A) some
rocks’ hardness, especially diamonds, is incomparable to any other
natural materialComparing hardness of a rock to another rock is illogical
we can compare one type of rock with another type of rock or
we can compare the hardness of one rock with the hardness of another rock
(B) the
hardness of some rocks, especially of diamonds, cannot be compared to the
hardness of any other natural materialoption B nails the comparison(C)
the fact that some rocks are hard, especially diamonds, is incomparable to
the hardness of any other natural material
the fact is illogically compared to the hardness
(D)
no natural material can be compared to the hardness of some rocks, especially of diamonds.
and no natural material should be! as stated in option A we cannot compare the natural material with the "hardness" of another natural material
(E) some
rocks’ hardness, and especially of diamonds, is difficult to be compared to any
other hard material.option E distorts the meaning of the sentence we are meant to compare the hardness of a natural material to the hardness of another rock and not with just any hard material in the nature.