= Solution
\b[The terms are $^1\Sigma_u^+$, $^1\Sigma_u^-$, $^1\Delta_u$, $^3\Sigma_u^+$, $^3\Sigma_u^-$ and $^3\Delta_u$.] The active configuration is $\pi_u^3\pi_g^3$. Each nearly filled $\pi$ shell has the angular-momentum possibilities of one hole, so coupling two distinguishable hole sets gives $\Lambda=0$ or $|\Lambda|=2$ with $S=0$ or $1$.
For $\Lambda=0$, the two arrangements of opposite projections combine with either reflection parity, hence both $\Sigma^+$ and $\Sigma^-$. Unlike the equivalent-electron case in part (a), neither spatial combination is excluded for either spin: the holes belong to different orbital shells. The inversion parity is $u^3g^3=u$. Counting degeneracies gives $1+1+2+3+3+6=16$, equal to the $4\times4$ choices of the two holes.
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