Which of the following stars is the coolest? sirius, a type a star arcturus, a type k star spica, a type b star antares, a type m star

A type M star which is majorly called red dwarf.

Explanation:

Stars are huge celestial bodies consisting of hydrogen and helium that produce light and heat from the nuclear reactions inside their cores. The main categories of spectral type are M, K, G, F, A, B, and O. The life cycles of stars follow patterns based mostly on their initial mass. A type M star which is majorly called red dwarf is the coolest. These stars are very tiny stars because they do not generate a lot of heat compared to others.

the answer is learned

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.