(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
是否应该是 ...is called...and is considered...?
A special Japanese green tea (which is) called ...在这里做定语。is considered 和contains平行。
"consider sth to do" is not wrong, i think. the problem in B is "delicacy fit for gourmet" is wordy compared to the "gourmet delicacy" in E. My opinon, just for your reference, hehe