My interpretations:
If you are sailing with two people on the boat, you would be required to have all three sails on the boat -- main, jib and spinnaker (including spinnaker pole), whether you use all or any of them.

If you are sailing single-handed, you would be required to have main and spinnaker on the boat (whether you use them or not) and would be required to NOT have a jib on the boat.

P.S. I am only giving my interpretations so Wouter and others can figure out how to clarify things, and not because I think my interpretations are right.