Answer:
Option C
Explanation:
Key Idea
The total number of electrons that the central metal ion appears to possess in the complex including those gained by it in bonding is called the effective atomic number of the central metal ion.
In the given complex ion [Fe(CN)6]3- the Fe is in +3 oxidation state. As we know that an atomic number of iron is 26. The number of electron in Fe3+ is 23. Each of the six cyanide molecules donates a pair of electrons so that EAN becomes
23+2 x6=35
