Question

based on this diagram, which type of stars would belong to spectral class m and have the highest luminosity? main - sequence stars giants white dwarfs supergiants

Explanation:

By observing the Hertzsprung - Russell (H - R) diagram shown, for spectral class M, giants have higher luminosities compared to main - sequence stars, white dwarfs, etc. Main - sequence stars in spectral class M have relatively low luminosities. White dwarfs are also low in luminosity for spectral class M. Giants are the ones with the highest luminosity among the options for spectral class M.

Answer:

Giants