Stereochemical descriptors for the atoms labeled $\mathrm{H}_{\mathrm{a}}$ and $\mathrm{H}_{\mathrm{b}}$ in the structure.(X) (Y) (Z) respectively are:
(a)X-homotopic, Y-enantiotopic and Z-diastereotopic
(b)X - enantiotopic, Y - homotopic and Z - diastereotopic
(c)X - diastereotopic, Y - homotopic and Z - enantiotopic
(d)X - homotopic, Y - diastereotopic and Z - enantiotopic