The correct sequence in the life cycle of a massive star is:
nebula, protostar, star, super red giant, supernova, neutron star
This sequence describes the typical stages a massive star goes through, starting from a nebula (the initial cloud of gas and dust), followed by the formation of a protostar, then the main sequence star, and eventually evolving into a super red giant. After the super red giant stage, the star undergoes a supernova explosion, leaving behind either a neutron star or, in some cases, a black hole.