To "Spin Up" the Rotation of a Neutron Star, Infalling

To "spin up" the rotation of a neutron star, infalling material from the binary companion impacts the surface at half the speed of light. Suppose the infalling material includes radioactive particles with a half-life T₀ measured when the particle is at rest. What is the half-life of these particles measured by an observer on the neutron star?

A) 0.5 T₀
B) 0.87 T₀
C) 1.15 T₀
D) 2 T₀