∵ABCD是平行四边形
∴AD ∥ BC,AB ∥ DC
∵△ADO ∽ △FBO,△ABO ∽ △EDO,△ADE ∽ △FCE,△FCE ∽ △FBA,△ADE ∽ △FBA五对才对.
∴共5对.
故选C.