A $0.20\mathrm{M}$ solution of $\mathrm{NaA}$ (HA: $K_a=2.0\times 10^{-5}$) is diluted to $0.0020\mathrm{M}$ at 298 K. Use $h=\sqrt{K_h/C}$ and $[\mathrm{OH}{}^{-}]=\sqrt{K_{h}C}$. Which statements are correct?

1. AThe degree of hydrolysis increases from $5.0\times 10^{-5}$ to $5.0\times 10^{-4}$, i.e. it becomes 10 times larger.
2. BThe pH decreases from $9.00$ to $8.00$.
3. C$K_h$ decreases 100-fold on dilution.
4. D$[\mathrm{OH}{}^{-}]$ after dilution is $1.0\times 10^{-5}\mathrm{M}$ (unchanged).