Which of the Following Statements About Cycloaddition Reactions Is Not $\sigma$

Which of the following statements about cycloaddition reactions is not true?

A) Cycloaddition reactions form a cyclic product with two new $\sigma$ bonds.
B) The course of the reaction is determined by the symmetry of the molecular orbitals of the products.
C) Cycloaddition reactions are concerted.
D) Cycloaddition reactions are stereospecific.