Recall the identity of Wilkinson catalyst

Wilkinson catalyst is the well-known homogeneous hydrogenation catalyst: $\mathrm{RhCl(PPh_3)_3}$ where $\mathrm{PPh_3}$ is triphenylphosphine.

Match with the given options

• A: $[(Ph_3P)_3RhCl]$
  This is exactly $\mathrm{RhCl(PPh_3)_3}$.
• B: $[(Et_3P)_3RhCl]$
  This has triethylphosphine instead of triphenylphosphine, so it is not Wilkinson catalyst.
• C: $[(Et_3P)_3IrCl]$
  Wrong metal and wrong phosphine ligand.
• D: $[(Ph_3P)_3IrCl]$
  Correct phosphine type but wrong metal; Wilkinson catalyst contains Rh, not Ir.

Conclusion

Therefore, Wilkinson catalyst is: $[(Ph_3P)_3RhCl]$

So the correct option is A.