The correct option is B Iron
The element is Iron. Iron which has resemblances with cobalt and nickel in its properties has been placed far away from these elements. Whereas, cobalt and nickel were placed in the same slot and in the same column of fluorine, chlorine and bromine. But cobalt and nickel have properties quite different from fluorine, chlorine and bromine. This is one of the demerits of Newlands' law of octaves.