下列符号中表示氧原子的是请选择ABCD,C+s'U0n8a/J*~8f,r'K,V6m)r7A6c;s1v6}7f2l
A.O2)r7A6c;s1v6}7f2l
B.O3)r7A6c;s1v6}7f2l
C.O)r7A6c;s1v6}7f2l
D.O2-)r7A6c;s1v6}7f2l