Answer:
Large mass.
Explanation:
A neutron star is one whose whole mass is concentrated in a small space. Thus, a neutron star has a very large mass and and a small radius. We know that Gravitational force
[tex]F= \frac{Mm}{r^2}[/tex]
That is F is directly proportional to mass and inversely proportional square of radius. Therefore, a neutron star has an immense gravitational attraction