Identify the correct stereochemical relationship amongst the hydrogen atoms $\mathrm{H}_{\mathrm{a}}, \mathrm{H}_{\mathrm{b}}$ and $\mathrm{H}_{\mathrm{c}}$ in the following molecule:
(a)$\mathrm{H}_{\mathrm{a}}$ and $\mathrm{H}_{\mathrm{b}}$ : enantiotopic
(b)$\mathrm{H}_{\mathrm{a}}$ and $\mathrm{H}_{\mathrm{b}}$ : diastereotopic
(c)$\mathrm{H}_{\mathrm{a}}$ and $\mathrm{H}_{\mathrm{c}}$ : enantiotopic
(d)$\mathrm{H}_{\mathrm{b}}$ and $\mathrm{H}_{\mathrm{c}}$ : diastereotopic