The First Step in the Disintegration of Uranium-238 Produces Thorium-234 $\alpha$

The first step in the disintegration of uranium-238 produces thorium-234.What particle is emitted in this reaction?

A) " $\alpha$ particle"
B) "neutron"
C) "proton"
D) " $\beta$ ^-particle"
E) " $\gamma$ ray"