\(\quad \quad \quad \quad \quad \quad \quad\quad (+4) \quad \quad \quad (A)\)
Oxidation state of \('S'\) in \(SO _{4}^{2-}\)
\(=+6\)
$(I)\, d^3\,\,\, (II)\, d^5 \,\,\,(III)\, d^6 \,\,\,(IV)\, d^8$
($en=$ એથીલીનડાયએમાઈન )