The correct order of relative stability of half filled and completely filled sub-shell is:
d5 < p3 < d10 < p6
As we know from our knowledge in atomic structure, if we are talking about the same principle quantum number, then p orbitals are more stable than d orbitals. But completely filled d orbital is more stable than half filled p orbital, because then it does not need more electrons to complete its orbital.Hence the correct order of relative stability of half filled and completely filled sub-shell is d5 < p3 < d10 < p6.