Critical Reasoning

Black Knight wrote:Modern physicians often employee laboratory tests, in addition to physical examinations, in order to diagnose diseases accurately. Insurance company regulations that deny coverage for certain laboratory tests therefore decrease the quality of medical care provided to patients.

Which one of the following is an assumption that would serve to justify the conclusion above?

The conclusion is that the quality of medical care is reduced.

(A) Physical examinations and the uncovered laboratory tests together provide a more accurate diagnosis of many diseases than do physical examinations alone.
This is correct, because if physical examination + lab tests = more accurate diagnosis, then by not doing the lab tests the quality of medical care is bound to decline.
(B) Many physicians generally oppose insurance company regulations that, in order to reduce costs, limit the use of laboratory tests.

Out of scope, the argument talks about better quality of medical care and not about reducing costs.
(C) Many patients who might benefit from the uncovered laboratory tests do not have any form of health insurance.
Those who do not have any insurance are not affected by the conslusion
(D) There are some illnesses that experienced physicians can diagnose accurately from physicians examination alone.
This actually negates the conclusion
(E) Laboratory tests are more costly to perform than are physical examinations.
out of scope
Will post the OA after some replies.