987第30题不大明白

(A) A special Japanese green tea called genmai-cha contains brown rice and is considered as a delicacy fit for a gourmet by most Japanese, though it is virtually unavailable outside Yokohama.

(B) Considered to be a delicacy fit for a gourmet by most Japanese, genmai-cha is a special green tea that contains brown rice, virtually unavailable outside Yokohama.

(C) A special Japanese green tea called genmai-cha contains brown rice and is considered a gourmet delicacy by most Japanese, though it is virtually unavailable outside Yokohama.

(D) Most Japanese consider genmai-cha, a special green tea which contains brown rice, as a delicacy virtually unavailable outside Yokohama.（C）

(E) Though virtually unavailable outside Yokohama, most Japanese consider genmai-cha, a special green tea that contains brown rice, a gourmet delicacy.

 答案是C。。。B哪里不对啊？