Which group of stars has a higher luminosity white dwarfs or giants?

giants has a higher luminosity

Explanation:

A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.Giant stars have radii up to a few hundred times the Sun and luminosity between 10 and a few thousand times that of the Sun.

While a white dwarf is a small, very dense, hot star that is made mostly of carbon. These faint stars(less luminous) are what remains after a red giant star loses its outer layers. Their nuclear cores are depleted. They are about the size of the Earth (but tremendously heavier)

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.