如图,在菱形ABCD中,∠B=100°,O是对角线AC的中点,过点O作MN⊥AD交AD于点M,交BC于点N,则下列结论错误的是( )

A.∠ACD=40°
B.OM=ON
C.AM+BN=AB
D.MN=
AC
0 150756 150764 150770 150774 150780 150782 150786 150792 150794 150800 150806 150810 150812 150816 150822 150824 150830 150834 150836 150840 150842 150846 150848 150850 150851 150852 150854 150855 150856 150858 150860 150864 150866 150870 150872 150876 150882 150884 150890 150894 150896 150900 150906 150912 150914 150920 150924 150926 150932 150936 150942 150950 366461
A.∠ACD=40°
B.OM=ON
C.AM+BN=AB
D.MN=