While all of the following sentences are correct, only one of them correctly defines a meso compound. The others merely express properties that are not unique to meso compounds alone. Which one is the definition?
a. A meso compound has stereogenic centers but is achiral.
b. A meso compound contains a plane of symmetry or a center of symmetry.
c. A meso compound cannot be resolved into enantiomers.
d. A meso compound possesses a mirror image but is superimposable on it.
e. A meso compound is optically inactive.