7. In a study of the effect of radiation from nuclear weapons plants on people living in areas near them, researchers compared death rates in the areas near the plants with death rates in areas that had no such plants. Finding no difference in these rates, the researchers concluded that radiation from the nuclear weapons plants poses no health hazards to people living near them.
Which one of the following, if true, most seriously weakens the researchers’ argument?
(A) Nuclear power plants were not included in the study.
(B) The areas studied had similar death rates before and after the nuclear weapons plants were built.
(C) Exposure to nuclear radiation can cause many serious diseases that do not necessarily result in death.
(D) Only a small number of areas have nuclear weapons plants.
(E) The researchers did not study the possible health hazards of radiation on people who were employed at the nuclear weapons plants if those employees did not live in the study areas.
(A) Out of scope; only nuke WEAPON manufacturing facilities are being scrutinized, NOT POWER plants.
(B) This is a strengthen, it further suggests that death rates are no different.
(D) Irrelevant, these small number of areas can still be compared to areas without nuke weapon manufacturers.
(E) This would be the tempting answer, but its still out of scope. The study strictly focuses on people who live in areas near weapons plants, so people who DO NOT LIVE in that area are irrelevant for the purposes of the study.
(C) By POE, we're left with (C). It addresses the subtle scope shift in the original info (measuring "death rates" while concluding about "health hazards"), and points out that death rates are not the only measure of health hazards.