Oncologists report that cancer patients with brain tumors who receive

Oncologists report that cancer patients with brain tumors who receive a combination of chemotherapy and radiation treatment do only as well, on average, as those patients who receive radiation treatment alone. Yet the oncologists state that chemotherapy is a necessary part of the treatment of all patients who receive them for tumors.

oncos believe combination of C and R is as good as only R on an average. Yet combination is important for people who receive them

Can you see the shift ???
we are finally talking of only those who actually receive combination. Let us see if it effects the reasoning

Which of the following, if true, most helps to reconcile the oncologists’ two claims?

A. Oncologists treat all cancer patients who have tumors with either radiation treatment alone or a combination of radiation and chemotherapy.
doesn't reconcile the two claims

B. Oncologists who prescribe these treatments make accurate determinations about which patients need both radiation and chemotherapy and which need radiation alone.
A very subtle hint... What was the shift ?? It was that people who receive the combination should take it.
The choice tells us that the people who are receiving combination have been accurately determined that is they require both ( reason may be anything).
Correct

C. Some tumors have been completely healed by a combination of radiation and chemotherapy.
this is covered in the average as there may be some which have been completely healed just by R

D. Some tumors that have been exacerbated by improper attempts at chemotherapy have been successfully treated with radiation.
Doesn't do much. Rather gives advantage of R

E. Patients with tumors in other areas of the body show more improvement when treated with both radiation and chemotherapy than when treated with radiation alone.
We are talking of a specific type and at a specific place. Out of scope

B