The stereoisomer of tartaric acid (2,3-dihydroxybutanedioic acid) shown is drawn with wedges. Which of the following statements about the compound shown are correct?

C2 and C3 each carry $\mathrm{H}$, $\mathrm{OH}$, $\mathrm{COOH}$ and the other $\mathrm{CH}(\mathrm{OH})\mathrm{COOH}$ unit, so both are stereocentres. In the drawing one centre is $(R)$ and the other $(S)$ with identical halves, so this is meso-tartaric acid: its eclipsed conformation has a mirror plane through the C2-C3 midpoint and it is optically inactive. The meso form is a diastereomer, not the enantiomer, of $(2R,3R)$-tartaric acid; the enantiomer of $(2R,3R)$ is $(2S,3S)$.