carcass
Clay absorbs radiation with time, releasing it only when heated. By heating a clay sculpture and measuring the radiation it releases, experts can determine to within a century when the sculpture was last heated. The original firing of the finished sculpture might be the occasion of that most recent heating.
Experts who obtain the year A.D. 1450 as an estimate for a given sculpture using the method described above would thereby most seriously undermine any claim that the sculpture was made in
(A) A.D. 1000
(B) A.D. 1400
(C) A.D. 1450
(D) A.D. 1500
(E) A.D. 1900
Since the argument tells us that experts can determine to within a century we can straight away reject options B-C-D as they are within a century of 1450 and can be legitimate claims.
Now we are left with A and E.
E can't be the correct answer as from the method in the argument we can conclusively say that the sculpture was last heated in 1450 and hence it existed in 1450 which means 1900 is definitely wrong.
Whereas for A, there could be a case in which the sculpture was created in 1000 but for some x-y-z reason was heated again in 1450, maybe to correct some cracks.
Hence E is the correct answer.