Tritium, a radioactive isotope of hydrogen, emits which of the following particles?

Tritium (${}^3\text{H}$ or $\text{T}$) is an isotope of Hydrogen with $1$ proton and $2$ neutrons. It is unstable and undergoes ${\beta }^{-}$ decay to form Helium-3.
$${}_1^3\text{H}⟶{}_2^3\text{He}+e^{-}+{\bar{\nu }}_e$$
Thus, it emits low-energy beta particles.