The reason for greater range of oxidation states in actinoids is attributed to

Solution & Explanation

\textbf{Answer:} (c) $5\mathrm{f}$, $6\mathrm{d}$ and $7\mathrm{s}$ levels having comparable energies. \textbf{Solution:} In actinoids the $5\mathrm{f}$, $6\mathrm{d}$ and $7\mathrm{s}$ energy levels lie very close to one another. Because these orbitals have comparable energies, electrons from all of them can be lost relatively easily and to varying extents. This allows actinoids to exhibit a much wider range of oxidation states than the lanthanoids. Hence option (c) is correct.