再请教一道大全的题目,答案不一

21.   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

大全给的答案是C,但是我记得哪里给的答案是A,

A 和C各有各的好处和不好的地方,A没有平行对称但是在介词指代方面没有歧义,C在平行对称方面很好,但是介词指代方面容易产生歧义.

到底应该选什么呢,请大家讨论下