Which Statement Is NOT True About the Diels-Alder Reaction

Which statement is NOT true about the Diels-Alder reaction?

A) It is a [4+2] cycloaddition reaction.
B) The diene must be in the s-cis conformation to react.
C) Most Diels-Alder reactions are reversible.
D) It is a sigmatropic rearrangement.
E) Electron donating groups on the diene and electron withdrawing groups on the dienophile favor product formation.