The two characteristics of a star that make it most likely to become a black hole are:
-
Its mass is greater than 20 times the mass of the sun. - Stars that are significantly more massive than the sun end their lives in a supernova explosion and can leave behind black holes.
-
It is dying. - Dying stars, particularly those that are massive, undergo processes that can lead to the formation of a black hole after exhausting their nuclear fuel.
The other two options, regarding mass equal to that of the sun and having an abundant supply of hydrogen, do not typically lead to black hole formation.