Radioactive iodine-131 releases $\beta$-particles and possesses a half-life of $8$ days. It decays into xenon-131. Which statement about this decay is correct?
- AAfter $8$ days no more $\beta$-particles are emitted.
- BAfter $8$ days the number of xenon-131 atoms has halved.
- CAfter $16$ days the iodine-131 has decayed completely.
- DAfter $16$ days the number of iodine-131 atoms has reduced to one quarter.