The diagram illustrates a decay chain with three $\alpha$-particles and one $\beta^{-}$ particle: $^{237}_{93}\mathrm{Np} \rightarrow Q \rightarrow R \rightarrow S \rightarrow T$ where the decays are $\alpha$, $\beta^{-}$, $\alpha$, $\alpha$ in that order. What is nuclide T?
- A$^{225}_{88}\mathrm{Ra}$
- B$^{231}_{88}\mathrm{Ra}$
- C$^{225}_{90}\mathrm{Th}$
- D$^{229}_{90}\mathrm{Th}$