Astatine, At, is placed underneath iodine in Group VII of the Periodic Table. Which of the following statements is most likely to be correct?
- A$\text{AgAt(s)}$ reacts with excess dilute aqueous ammonia to form a solution of a soluble complex.
- BAstatine and $\text{KCl(aq)}$ react to form $\text{KAt(aq)}$ and chlorine.
- C$\text{KAt(aq)}$ and dilute sulfuric acid react to form white fumes of $\text{HAt(g)}$.
- D$\text{NaAt(s)}$ and concentrated sulfuric acid react to form astatine.