Identify the MOs that react to form cyclohexene. HOMO of 1,3-butadiene and LUMO of ethylene LUMO of 1,3-butadiene and LUMO of ethylene HOMO of 1,3-butadiene and HOMO of ethylene LUMO of 1,3-butadiene and LUMO of 1,3-butadiene HOMO of 1,3-butadiene and HOMO of 1,3-butadiene