请教一个问题

水苹苹

The distinctive hereditary tartansthat are alleged to be worn since antiquity by members of the Highland clans were in fact designed by Scottish woolen manufacturers in the eighteenth and nineteenth centuries.

(B) alleged to have been worn
(D) alleged as having been worn

答案选B，想问下，D选项错在哪了？谢谢~~

水苹苹

虽然这个问题NN们看起来很简单，但是也为我解答一下吧，谢谢啦~~~~