The correct option is A chlorotris(triphenylphosphine)rhodium(I)
The IUPAC name of the Wilkinson's catalyst [RhCl(PPh3)3] is chlorotris(triphenylphosphine)rhodium(I) because the oxidation state of Rh metal in the complex is +1.
x+(−1×1)+0=0
x=+1.
Ligands are named first in alphabetical order, irrespective of its charge, hence ''chloro'' will be written prior to "triphenylphosphine''.
Hence, the correct option is (a).