The correct geometries for the metal carbonyl clusters, A-CA. $\left[\mathrm{Ru}_{6}(\mathrm{CO})_{17}\mathrm{B}\right]^{-}$ B. $\left[\mathrm{Os}_{6}(\mathrm{CO})_{18}\mathrm{P}\right]^{-}$ C. $\left[\mathrm{Os}_{4}(\mathrm{CO})_{16}\right]$ are
(a)A: pentagonal bipyramidal, B: trigonal prismatic, and C: tetrahedral
(b)A: pentagonal bipyramidal, B: octahedral, and C: square
(c)A: octahedral, B: trigonal prismatic, and C: tetrahedral
(d)A: octahedral, B: trigonal prismatic, and C: square