= Solution
For \b[A, linear <nitrogen> coordination with predominantly nitrile-like bonding] is consistent with all three measurements:
$$
\mathrm{M\leftarrow N\equiv C-S^-}.
$$
The short C–N and long C–S distances correspond approximately to a <triple bond> and a <single bond>. An approximately $sp$ <nitrogen> donor has its donor <lone pair> directed along the N–C axis, explaining the linear M–N–C angle.
For \b[B, bent <nitrogen> coordination with increased $\mathrm{^-N=C=S}$ <chemical resonance> character] accounts for the longer C–N and shorter C–S bonds. In this limiting description both internal bonds have substantial double-bond character and <nitrogen> is approximately $sp^2$. One <nitrogen> <lone pair> can bind a <metal> with an M–N–C angle near $120^\circ$; alternatively, donation of both <nitrogen> <lone pairs> can give a trigonal, nitrogen-bridging unit:
$$
\begin{array}{c}
\mathrm{M}\\[-2pt]
\diagdown\\[-3pt]
\mathrm{N=C=S}\\[-3pt]
\diagup\\[-2pt]
\mathrm{M'}
\end{array}
$$
The nitrogen-bridging drawing is a compatible proposed bonding mode, but the listed internal distances and one angle alone do not prove the number of attached <metals>. In particular, B cannot be identified simply as terminal <sulfur> coordination: the specified angle explicitly contains an M–N bond. <resonance structures> explain relative <bond orders>; they do not imply an isolated <coordination ligand> with permanently localized integer bonds.
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