In GMAT CR, pay attention to details, or get smoked!

With the subject of this thread in mind, see whether you get this one right.

Rising global temperatures have led to ecological issues that have affected the growth of the staple crop, madinga, in Guadelaga. As this process has continued, the output of madinga in Guadelaga has decreased. If temperatures continue to increase, the people of Guadelaga will soon have to change their diets, as they will no longer have access to sufficient madinga.

The answer to which of the following would be the least useful in assessing the validity of the above conclusion?

(A) Are there certain strains of madinga that are not currently commonly grown in Guadelaga and that would thrive in the new conditions?

(B) Are there places other than Guadelaga where madinga can be grown and where temperatures can be expected to remain similar to or lower than temperatures currently seen in Guadelaga?

(C) If new measures being adopted were to cause global temperatures to stabilize near current levels, would the size of Guadelaga's madinga crop stabilize near current levels?

(D) Would using relatively complex and currently rarely used biodiverse farming methods ameliorate the effects of higher temperatures on the ecology that supports the growth of madinga?

(E) To what degree does Guadelaga's current madinga crop exceed the dietary consumption of madinga by the people of Guadelaga?

OA below.