Answer:
The correct answer is pulsar.
Explanation:
Protostar : Its a young star with contracting mass which gains mass from its parent molecular cloud. At this stage fusion process does not start.
Red dwarf: A star having lower surface temperature , luminosity, mass and size than of the sun.
White dwarf : its an ultimate stage for an average mass star like sun . its a small dense star with size relatively equal to planet.
Pulsar : A rotating neutron star that emits beam of radio waves and other electromagnetic radiations.
Black hole: It is region of space time with very strong gravitational pull that even smallest particle or electromagnetic wave is incapable to escape it.
