Nuclide $^{42}_{20}\text{Ca}$ is produced through $\beta^{-}$ decay. What are the nucleon (mass) number and proton (atomic) number of the unstable nuclide that decayed by $\beta^{-}$ emission to produce the calcium nuclide?
- Anucleon number 41; proton number 19
- Bnucleon number 41; proton number 21
- Cnucleon number 42; proton number 19
- Dnucleon number 42; proton number 21