Which stars have low temperatures and high luminosities

A. Red giants

B. White dwarfs

C. Main sequence stars

Red giant.

Explanation:

Red giant star is the last stage of stellar evolution. Red giant star has the size of around 100 million to 1 billion kilometers in diameter.

Red giant star has low temperature, ranges only from 2200 to 3200°C. The red star shows high luminosity more than 3000 times as compared with sun.

Thus, the correct answer is option (A).

Red giants have low temp but high luminosity while white dwarfs have a very high temp but low luminosity main sequence stars are just mixed