求教OG12-Q82，一道support的问题

82. 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 the 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.
(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.

正确答案是D。我觉得C、D都不可以support呀~这道题应该关注的是trade。OG上对C的解释是说因为贸易，所以贸易的交流才导致了建筑风格的影响，那这样解释的话D岂不是也可以解释成因为有了trade，所以才使东非对北非的动物有了认识？
总感觉C像是对结果多往下推了一步才得出support的！纠结了~

谢谢大家~