Two groups of laboratory mice were injected with cancerous cells. One

IMO the answer should be A
Basic Crust: stress induced due to the disoriented rotation of the cage enhanced the cancerous growth in the mice
Assumption: 1. No other reasons for the cancerous growth
2. Disoriented rotation is the only cause
A: our answer. Negating this assumption destroyed our conclusion
B: This could be an assumption but not related to what the question stem asks. If the stem would have asked to weaken the conclusion then this option would make a good case. Plus we don't know if the difference in dosage makes any difference whatsoever.
C: then why the disorientation and rotation? Eliminate since its irrelevant
D: Out of scope. with/without injections is not the case of argument here
E: Our concern is stress and not the disorientation and rotation. Hence not related to our query, eliminate

Premises: Two groups of laboratory mice were injected with cancerous cells. (Let us say Group1)One group’s cages were rotated in a disorienting manner. Two-thirds of these mice developed cancers. (Let us say group 2) One-tenth of the mice in stationary cages developed cancers.

Conclusion - The researchers concluded that stress enhances the development of cancer in laboratory mice.
The researchers’ conclusion logically depends on which of the following assumptions?
(A) Rotating the cages in disorienting manner produced stress in the mice in those cages.
(B) The injections given to the two groups of mice were not of equal strength.
(C) Injecting the mice with cancerous cells caused stress in the mice.
(D) Even without the injections the mice in the rotated cages would have developed cancers.
(E) Even the rotation of cages in a manner that is not disorienting is likely to produce stress in mice in those cages.

We can see from the premises that the incidences of cancer in group 1 were more than group 2. just keep in mind that this has something to do with rotation in a disorienting manner.
Conclusion talks about stress.
Missing link: relationship between disorienting rotation and stress

Disorienting rotation--cancer + (Assumption) ----> Stress---> cancer Hence, A
B. Wrong because wither group could have gotten the injection with more strength.
C. in this case, both groups have an equal chance of getting cancer
D. out of scope
E. this compares oriented rotation. has nothing to do with disoriented rotation vs stationary.

OR just use LEN technique on A
(A) Rotating the cages in disorienting manner had not necessarily produced stress in the mice in those cages. the conclusion falls apart.

AkritaJam Thanks for pointing out the missing link.....Crystal Clear now (y)
Well Explained.....

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