A radium nucleus whose nucleon number is $226$ undergoes decay by releasing an $\alpha$-particle. Radium has proton number $88$. What are the nucleon number and proton number of the nucleus formed in this decay?
- Anucleon number $222$, proton number $86$
- Bnucleon number $222$, proton number $87$
- Cnucleon number $226$, proton number $86$
- Dnucleon number $226$, proton number $87$