GMAT Critical Reasoning (CR) | Re: Joseph: Health insurance premiums are growing at an alarming

A. Doctors are generally able to determine, with great reliability, which diagnostic procedures and tests would yield the most effective results --> that's great and all; this is what doctors are paid to do, but it doesn't add anything to the main point

B. Tests and diagnostic procedures do not make up an insignificant portion of the bills that are sent to insurers --> Correct! If these tests make up an insignificant portion of the bills, the argument will collapse.

C. Insurance companies
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