What is the ultimate end of a high mass star that has a core about 2.8x the mass of our sun?

A. a pulsar

B. a black hole

C. a brown dwarf

D. a magnetar

A) Pulsar

Explanation:

Pulsars are collapsed cores of stars usually supergiant stars

this happens when a supernova leaves behind the star core that has no outer protection layer of high gravity so the core collapses in on itself to create a very high magnitude star and also has trillions more mass.

A

Explanation:

It is formed after the star has ended its star cycle into a supernova. The star collapsed into a neutron star that is smaller than the progenitor star but has inherited angular momentum. IT, therefore, spins faster emitting electromagnetic radiation that seems to pulsate.