4.下列化合物双键的键长的大小原序正确的是 () 。-|||-(1) (H)_(2)=C(H)_(2) (2) (3) (H)_(2)=CH-CH-C(H)_(2)-|||-A. (1)-(3)gt (2)-|||-B. (1)gt (21)(3)-|||-C. (2)gt (3)gt (1)-|||-D. (3)gt (11)gt (2)