The extent of crystal field splitting in octahedral complexes of the given metal with particular weak field ligand are:
a. Fe(III) < Cr(III) < Rh(III) < Ir(III)
b. Cr(III) < Fe(III) < Rh(III) < Ir(III)
c. Ir(III) < Rh(III) < Fe(III) < Cr(III)
d. Fe(III) = Cr(III) < Rh(III) < Ir(III)