Question

question 11
after a massive star produces a supernova explosion, the remains of the stellar core
may be a white dwarf, neutron star, or a black hole
will always be a neutron star
will always be a black hole
may be either a neutron star or a black hole
may be either a white dwarf or neutron star

Explanation:

A white dwarf forms from a low - mass star, not a massive star that goes supernova. A massive star's core after supernova: if its mass is between about 1.4 - 3 times the Sun's mass, it becomes a neutron star; if mass is greater than 3 times the Sun's mass, it becomes a black hole. So it can't always be a neutron star or always be a black hole.

Answer:

may be either a neutron star or a black hole