GMAT Sentence Correction (SC) | Though most laypeople do not know the difference between classical and

Source: McGraw Hill GMAT

Though most laypeople do not know the difference between classical and clinical homeopathy, practitioners assert that clinical homeopathy is directed toward particular organs and tissues, andhas contributed more to scientific research.

A. has contributed more to scientific research
B. contributed to more scientific research
C. it contributes more scientific research
D. contribute to most scientific research
E. had more scientific contributions to research
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