In a Binary Star System,an Unseen Component Is Found to Have

Multiple Choice

In a binary star system,an unseen component is found to have a mass of about 8 solar masses.If this were a normal star,then it would be visible,so it must be a collapsed object.Theoretical considerations tell us that it must be a

A) white dwarf.
B) black hole.
C) neutron star.
D) brown dwarf.