4-Hydroxy-4-methylpentan-2-one is dehydrated with dilute $\mathrm{NaOH}$. Which statements are correct?

1. AThe main alkene formed is 4-methylpent-3-en-2-one (mesityl oxide).
2. B4-Methylpent-4-en-2-one is the main product.
3. CThe intermediate is the enolate formed by loss of H from C-3.
4. D$\mathrm{OH}{}^{-}$ is lost from C-4 as the electrons of the enolate move to form the $\mathrm{C}{}_3=\mathrm{C}{}_4$ bond.