IMO D. The argument: East African & North African (near Mediteranean coast) began trading to each other no earlier than 10 century

A sudden increase in the production of elephant ivory artifacts on the Mediterranean
coast of North Africa occurred in the tenth century. Historians explain this increase as
the result of an area opening up as a new source of ivory and argue on this basis that the
important medieval trade between North Africa and East Africa began at this period.
Each of following, if true, provides some support for the historians’ account described
above EXCEPT:
A. In East Africa gold coins from Mediterranean North Africa have been found at a
tenth-century site but at no earlier sites -->gold coins mean business, so this strengthens that their business - East & North Africa near Mediteranean, began no earlier than 10-century
B. The many surviving letters of pre-tenth-century North African merchants include
no mention of business transactions involving East Africa --> this eliminates any possibility that North & East have trading to each other earlier than 10 century, thus strengthening the argument
C. Excavations in East Africa reveal a tenth-century change in architectural style to
reflect North African patterns -->strengthen. From 10 century, East African has been influenced by North African's architecture. This means they began a relation at 10 century, and it was likely business relation
D. Documents from Mediterranean Europe and North Africa that date back earlier
than the tenth century show knowledge of East African animals -->this mentions about pre 10 century but shows no relations between North African Mediteranean coast & East Africa. It neither strengthens nor weakens, thus the best
E. East African carvings in a style characteristic of the tenth century depict seagoing
vessels very different from those used by local sailors but of a type common in
the Mediterranean --> strengthen. At 10 century, East African had seagoing evidences related to that of Mediteranean coast, and because those can be of the Mediteranean coast of North African, so it connects East African & North African mediteranean coast

Cant recall which set but must be from 17 or 18 verbal set

Solution is D

Using the CR bible approach:

Question is of Family #2 -> help
Question type is StrengthenX (the correct answer does not strengthen/support the argument). The correct answer is either neutral or weakens the argument.

All answers but D either strengthen or support the argument. D is neutral. Hence, D is correct.

Can someone post the one that strengthens this argument the most....

I go with A.

Because gold coins --> Business --> from 10th century...

Please provide your answers as well.
_________________

Labor cost for typing this post >= Labor cost for pushing the Kudos Button
http://gmatclub.com/forum/kudos-what-are-they-and-why-we-have-them-94812.html

A sudden increase in the production of elephant ivory artifacts on the Mediterranean coast of North Africa occurred in the tenth century. Historians explain this increase as the result of an area opening up as a new source of ivory and argue on this basis that the important medieval trade between North Africa and East Africa began at this period.
Each of following, if true, provides some support for the historians’ account described
above EXCEPT:
A. In East Africa gold coins from Mediterranean North Africa have been found at a tenthcentury site but at no earlier sites.
B. The many surviving letters of pre-tenth-century North African merchants include no mention of business transactions involving East Africa.
C. Excavations in East Africa reveal a tenth-century change in architectural style to reflect North African patterns.
D. Documents from Mediterranean Europe and North Africa that date back earlier than the tenth century show knowledge of East African animals.
E. East African carvings in a style characteristic of the tenth century depict seagoing vessels very different from those used by local sailors but of a type common in the Mediterranean

The conclusion is: the important medieval trade between North Africa and East Africa began at this period (10th century). We have to find an option that does not strengthen the conclusion.
A: Coins from N. Africa have been found at E. African sites dating back to 10th century, but not at sites older than 10th century. (Does strengthen the argument)
B: Surviving letters from pre/ before 10th century make no mention of any trade between North and East Africa. Does strengthen the argument).
C: Excavations in E. Africa changed around 10th century to reflect N. African architecture. Does strengthen.
D: Knowledge of E. African animals (possibly elephants- the source of ivory also) before 10th century. It could mean that N. Africa knew of elephants before 10th century, and the trade in Ivory began before the 10th century. (Weakens the argument)
E: Seems irrelevant as there is no reference to N. Africa.

A. supports
B. supports
C. supports
D. weakens
E. supports

Hence the weakens is the correct answer
_________________

Regards,
Harsha

Note: Give me kudos if my approach is right , else help me understand where i am missing.. I want to bell the GMAT Cat

Satyameva Jayate - Truth alone triumphs

hi, i'n new here.

i know the OA is D and i understand why. But before i read the answer choices, i assumed the supporting answer should say that North and East Africa traded 'IVORY', but not anything else. Shouldn't that make more sense?

wish i've explained my question clearly.

i mean the historians think that the beginning of trade during that time can explain the increase in the production of ivory artifacts, right?
but the answer choices, i mean the supporting ones, only emphasize on the beginning of trade at time, shouldn't they focus on the thing they are trading for?

I mean if NA and EA began the trade at that time, but EA never buy any ivory artifacts from NA, then how can it support historians' explanation?

hi maggie,

the highlited portion is not correct IMO.

A sudden increase in the production of elephant ivory artifacts on the Mediterranean coast of North Africa occurred in the tenth century. Historians explain this increase as the result of an area opening up as a new source of ivory and argue on this basisthat the important medieval trade between North Africa and East Africa began at this period.

IN THE ARGUMENT IT SAYS THAT A NEW SOURCE OF IVORY WAS FOUND ...AND ON THE BASIS OF THAT HISTORIANS ARGUE THAT :the important medieval trade between North Africa and East Africa began at this period.===>SO TRADE DOESNT LED TO INCREASE IN THE PRODUCTION OF ARTIFACTS.

hope it helps[/quote]

Hi, thanks! that really helps.
so a new source led to the increase right? then why does the author need to mention the trade here? i don't get this part.
"argue on this basis" means "argue on the basis of the new source of invory" right?

DO NOT PREPHRASING, i will keep that in mind
so one thing just for sure, the author included the ivory part just to introduce the trade thing,
"trade thing" is "the historian's account" ( in the question stem), right?