Answer
See explanation below.
Work Step by Step
a. Ca[IrF6]- here central atom is Ir, Ir4+ electronic configuration is [Xe]4f14 5d4.It has 5d electrons in Ir4+
b. [HgI4]22-here central atom is Hg, Hg2+ electronic configuration is [Xe]4f14 5d10.It has 10d electrons in Hg2+
c. [Co(EDTA)]22-here central atom is Co, Co2+ electronic configuration is [Xe]3d7.It has 7d electrons in Co2+