27.下圖為下列何者單糖之正確結構?(A) α-D-葡萄呋喃糖(a-D-glucofuranose) H HO CH₂OH(B) β-D-葡萄呋喃糖(β-D-glucofuranose) H H HO(C) a-D-葡萄吡喃糖(a-D-glucopyranose) OH H HO H(D) β-D-葡萄吡喃糖(β-D-glucopyranose)