In the acid-catalysed ${\mathrm{S}}_{\mathrm{N}}1$ hydrolysis of $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{Br}$ in water, the steps are: (1) ionisation to $(\mathrm{CH}{}_3){}_3\mathrm{C}{}^{+}$; (2) capture by $\mathrm{H}{}_2\mathrm{O}$ to give $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{OH}{}_2{}^{+}$; (3) loss of $\mathrm{H}{}^{+}$ to give $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{OH}$. Which statements are correct?

1. AThe path has three transition states
2. BThe tert-butyl cation lies at an energy maximum
3. CThe path has two reactive intermediates
4. DThe ionisation (step 1) is the rate-determining step