What are the geometric figures commonly used in the group of buildings in the Temple of Heaven? A: Rectangle B: Circular C: Square D: Octagon

Which of the following IS/ARE wrong about pi-yong? A: double-eave, yellow glazed-tile roof. B: a round ground floor plan with a circular pond around. C: a regular octagon shape made of beams in the center D: the place where Emperor Qianlong gave lectures in the Imperial Academy