The statement that is true of the brightest stars is: Many are supergiants.
Bright stars in the night sky often include supergiant stars, which are among the most luminous and massive types of stars. While some bright stars can be part of the main sequence, not all of them are; for example, many of the brightest stars are indeed supergiants. White dwarfs, on the other hand, are not typically among the brightest stars we see, as they are faint remnants of stars that have exhausted their nuclear fuel. Additionally, bright stars come in various colors and types, so they are not exclusively yellow.