Question

what will a medium - mass star become at the very end of its life cycle?
○ a red giant
○ a black hole
○ a black dwarf
○ a neutron star

Explanation:

A medium-mass star (like our Sun) first expands into a red giant, then sheds its outer layers to leave a white dwarf. Over trillions of years, the white dwarf cools completely and stops emitting light, becoming a black dwarf, which is the final stage of its life cycle. Red giants are an intermediate stage, black holes and neutron stars form from much more massive stars.

Answer:

a black dwarf