d
\(\begin{array}{*{20}{c}}
{Ac}&{Th}&{Pu}&U&{Np}&{Pu}&{Am}&{Cm}&{Bk}&{Cf}&{Es}&{Fm}&{Md}&{No}&{Lr} \\
{ + 3}&{}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 3}&{ + 2}&{ + 3} \\
{}&{ + 4}&{ + 4}&{ + 4}&{ + 4}&{ + 4}&{ + 4}&{ + 4}&{ + 4}&{}&{}&{}&{}&{}&{} \\
{}&{}&{ + 5}&{ + 5}&{ + 5}&{ + 5}&{ + 5}&{}&{}&{}&{}&{}&{}&{}&{} \\
{}&{}&{}&{}&{ + 6}&{ + 6}&{ + 6}&{}&{}&{}&{}&{}&{}&{}&{} \\
{}&{}&{}&{ + 6}&{ + 7}&{ + 7}&{}&{}&{}&{}&{}&{}&{}&{}&{}
\end{array}\)
\(\therefore \) \(Np\) and \(Pu\) has maximum no. of possible oxidation states.