Answer:
c. Main Sequence
Step-by-step explanation:
90% of the stars in space are in the main sequence stage.
Nebula is a cloud of dust and hot gases where stars are born. Giant and white dwarf are types of stars.
A plot of star temperature vs luminosity is used to classify all the stars. This plot is known as HR diagram. When plotted on the HR diagram, 90% of the known stars lie on the main sequence stage of the HR Diagram.