设红、紫四边形的高相等为h1,黄、白四边形的高相等,高为h2,
则S1=DE?h1,S2=AF?h2,S3=EC?h1,S4=FB?h2,
因为DE=AF,EC=FB,
故A错误;
S1+S4=DE?h1+FB?h2=AF?h1+FB?h2,
S2+S3=AF?h2+EC?h1=AF?h2+FB?h1,
故B错误;
S1S4=DE?h1?FB?h2=AF?h1?FB?h2,
S2S3=AF?h2?EC?h1=AF?h2?FB?h1,
所以S1S4=S2S3,
故C正确;
故选:C.
设红、紫四边形的高相等为h1,黄、白四边形的高相等,高为h2,
则S1=DE?h1,S2=AF?h2,S3=EC?h1,S4=FB?h2,
因为DE=AF,EC=FB,
故A错误;
S1+S4=DE?h1+FB?h2=AF?h1+FB?h2,
S2+S3=AF?h2+EC?h1=AF?h2+FB?h1,
故B错误;
S1S4=DE?h1?FB?h2=AF?h1?FB?h2,
S2S3=AF?h2?EC?h1=AF?h2?FB?h1,
所以S1S4=S2S3,
故C正确;
故选:C.