钻牛角尖专业户问OG 12 31时态问题

Unlike the conviction held by many of her colleagues that genes were relatively simple and static, Barbara McClintock adhered to her own more complicated ideas about how genes might operate, and in 1983, at the age of 81, was awarded a Nobel Prize for her discovery that the genes in corn are capable of moving from one chromosomal site to another.


(A) Unlike the conviction held by many of her colleagues that genes were
(B) Although many of her colleagues were of the conviction of genes being
(C) Contrary to many of her colleagues being convinced that genes were
(D) Even though many of her colleagues were convinced that genes were
(E) Even with many of her colleagues convinced of genes being  
正确选项是D但是为什么用WERE呢？这是讲的某种客观存在自然规律不是么？还望NN解答！