∴ED=AC,AE=CD
∫△ADE and △ABC are isosceles right triangles.
∴AE=AD=CD,AB=AC=DE
∴AD? +CD? =AC?
∴△ACD is an isosceles right triangle
So △ CDE △ is not good
∴CE=BD
∫∩BAD =∩BAE
∴△ABD≌△ABE
Therefore, ADB =∩AEB.
∫△ACE?△ABD
So ∩ bad =∩ACE
∴∩BGC=90 =∩CGD
Because ∩AEF=∩GCD.
∴△AEF∽△GCD
∴CD/EF=CG/AC
That is CD*AE=EF*CG.
So choose d