Answer: The correct answer is Option C.
Step-by-step explanation:
Oxidation state is the number which is assigned to an element when it gains or looses electrons. If the element gains electron, it will attain a negative oxidation state and if the element looses electrons, it will attain a positive oxidation state.
We take the oxidation state of iron atom be 'x'.
Oxidation state of oxygen atom = -2
Evaluating the oxidation state of iron atom in
:

Hence, the correct answer is Option C.