THE CORRECT ANSWER IS B. THE ORIGINAL SENTENCE CONTAINS THE WORDY...
25. The correct answer is B.
The original sentence contains the wordy expression "are different
than", which can be replaced with the more concise "differ from."
Moreover, "different than" should not be used when comparing two
nouns (modern pigments vs. older ones). The correct expression is
"different from". Also, "the ones" can be replaced with the more
concise "those". The use of "because" here is also problematic. It is
better to state that X differs from Y "in that..." Finally, the pronoun
"they" is ambiguous here. Does it refer to the old pigments or to the
new?
The only choice to address all these issues is B.