the answer is d.

in a) Fe3+ may be reduced to Fe2+ and I- may get oxidised to I2.

IN b) PbI4 is unstable as lead is in +4 oxidation state in which it is unstable and get automatically reduces to Pb2+.

In c)it is a mixture of strong acid,strong base. which obviously wont coexist

in d) there is no reaction possible.