这道题颠覆了我的“世界观”

While the owner of a condominium apartment has free and clear title to the dwelling, owners of cooperative apartments have shares in a corporation that owns a building and leases apartments to them.
(A) While the owner of a condominium apartment has free and clear title to the dwelling,
(B) The owner of a condominium apartment has free and clear title to the dwelling, but
(C) Whereas owners of condominium apartments have free and clear title to their dwellings,
(D) An owner of a condominium apartment has free and clear title to the dwelling, whereas
(E) Condominium apartment owners have a title to their dwelling that is free and clear, while

白勇比较第七章：比较结构  27题

根据原句的合理重心和结构，排除了B,D,E.

最后我选择了A，因为我认为C中代词their和句尾的代词them违背了“一句话中，相同的代词（包括they,them,their等）必须指代相同”这一代词指代原则。

而答案却选了C，解释为：意思对比的结构，形式要对称。

我就纳闷了，难道代词指代都不是“原则性的错误”了么？？？？？？？？