Answer
Structure a and structure d are meso compounds.
Work Step by Step
a) This is a meso compound because it has a symmetrical plane. Also it has a r and s conformation carbon which makes it meso.
b) This is not a meso compound because both of its carbons are r conformation.
c) This is not a meso compound because it does not have a symmetrical plane.
d) This is a mesocompound because it has a symmetrical plane. The two carbons are r and s conformation which makes it meso.
