Answer:
The correct answer is option d, that is, the star's absolute magnitude.
Step-by-step explanation:
The Hertzsprung-Russell diagram or the H-R diagram also called the color-magnitude diagram. It demonstrates the association of the color of the stars (temperature) with the luminosity of the star or absolute magnitude. The stars apparent magnitude at a distance of ten Parsec from Earth is known as the absolute magnitude of the star.