One thorium isotope has nucleon number $232$ and proton number $90$. It decays to produce a different thorium isotope with nucleon number $228$. Determine how many alpha particles and beta particles are emitted by the thorium nucleus during this decay.
- Aalpha particles $0$, beta particles $4$
- Balpha particles $1$, beta particles $0$
- Calpha particles $1$, beta particles $2$
- Dalpha particles $2$, beta particles $1$