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.