The compound shown is $(S)$-butan-2-ol. Which of the four wedge drawings shown as options have the $(R)$ configuration at their stereocentre?

Each structure is assigned by ranking the four groups and viewing with $\mathrm{H}$ away. P is butan-2-ol with the opposite arrangement to the compound shown, so it is $(R)$. Q is 2-chlorobutane; priorities $\mathrm{Cl}>\mathrm{C}{}_2\mathrm{H}{}_5>\mathrm{CH}{}_3>\mathrm{H}$ give a clockwise sequence, $(R)$. R is alanine; $\mathrm{NH}{}_2>\mathrm{COOH}>\mathrm{CH}{}_3>\mathrm{H}$ runs anticlockwise, $(S)$. S is lactic acid; $\mathrm{OH}>\mathrm{COOH}>\mathrm{CH}{}_3>\mathrm{H}$ runs anticlockwise, $(S)$.