Answer:
D alpha particles
Step-by-step explanation:
Radioactive U-238 will decay into Thorium -232 by emitting alpha particles in the process of nuclear fission.
Nuclear fission is the radioactive decay process in which a heavy nucleus spontaneously disintegrates into two lighter ones and several other particles with a large release of energy.
U-238 → Th-232 + alpha particles + 2 neutrons + energy
This way the mass and atomic numbers are conserved;