ngk4mba3236 wrote:so, basically it boils down to what you said earlier (TWO LOGICAL INTERPRETATIONS of an answer choice lead to ambiguity) -

Correct.

p.s: however, the second interpretation, which is deemed correct over the other, seems to be by some brute force as GMAT has deemed it correct!

The only answer choice that is error free and conveys a clear meaning is E.
Thus, the meaning conveyed by E must be the intended meaning.

GMATGuruNY wrote:

p.s: however, the second interpretation, which is deemed correct over the other, seems to be by some brute force as GMAT has deemed it correct!

The only answer choice that conveys a clear meaning is E.

this is where my concern is because as we've discussed above that meaning in A is logical but E is the OA. it appears to me that meaning in E is considered correct because GMAT has deemed it correct!

however your other reason to eliminate A (re more than one interpretations) should be suffice to eliminate A.

ngk4mba3236 wrote:this is where my concern is because as we've discussed above that meaning in A is logical but E is the OA. it appears to me that meaning in E is considered correct because GMAT has deemed it correct!

however your other reason to eliminate A (re more than one interpretations) should be suffice to eliminate A.

In A, the meaning conveyed by not normally found cannot be deemed logical because the meaning conveyed by this modifier is UNCLEAR.
As discussed above, a reader cannot be certain whether this modifier is intended to modify tissues or tooth and bone.
It is contradictory to deem the conveyed meaning both unclear and logical.

Moreover -- as suggested in my original post -- the usage of because in A conveys a nonsensical meaning.
Option A implies the following:
The composition of teratomas CAUSES them to be unusual.
This meaning makes no sense.
The composition does not FORCE teratomas to be unusual.
Rather, the composition is an ASPECT of teratomas that IS unusual.

For both these reasons, eliminate A.