Question 12In quadrilateral $ABCD$, $M,N$ are midpoints of $AB,DC$, respectively. Segments $AN,BN,DM,CM$ divide it into seven regions of different areas $S_1,S_2,\ldots,S_7$ as shown. Which relationship is true? $S_2+S_4=S_6$$S_1+S_7=S_4$$S_2+S_3=S_4$$S_1+S_6=S_4$None of the above
