GMAT Sentence Correction (SC) | Re: In an effort improve the quality of patient care, Dr. Lydia

In an effort improve the quality of patient care, Dr. Lydia Temoscho is directing one of several clinical research projects that seek to determine the extent that psychological counseling helps to supplement the medical treatment of serious disease.

(A)seek to determine the extent that psychological counseling helps to supplement
(B)seek to determine how helpful psychological counseling is in supplementing
(C)seeks to determine how helpful psychological counseling is to supplement
(D) seeks
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