The ketone shown is treated with LDA in THF at $-78^{\circ }$C and then trimethylsilyl chloride. Which structure shown is the silyl enol ether formed under kinetic control?

The ketone shown is 4-methylpentan-2-one. LDA at $-78^{\circ }$C removes a proton from the less substituted and less hindered CH${}_3$ (kinetic enolate), and the oxygen of this enolate is trapped by the oxophilic silicon of $\mathrm{Me}{}_3\mathrm{SiCl}$ to give the terminal silyl enol ether. Silylation of the CH${}_2$ side would give the more substituted (thermodynamic) silyl enol ether, and Si-C bonded products are not formed from enolates with $\mathrm{Me}{}_3\mathrm{SiCl}$.