下面各组数中，哪组中两式不相等？请选择DCBA'T2{*A-M5C:y-B5?1{7m4V5Q
A．a +a +a和3a-B5?1{7m4V5Q
B．a+a +a和a³-B5?1{7m4V5Q
C．a×a和a²-B5?1{7m4V5Q
D．2 ×2和2²-B5?1{7m4V5Q