Which of the following element exhibits maximum oxidation state

Which of the following exhibits maximum oxidation state of vanadium?

Which of the following exhibits maximum oxidation state of vanadium?

Manganese exhibits maximum oxidation state in

Manganese exhibits maximum oxidation state in:

Which of the following transition elements exhibit +8 oxidation state

Which of the following transition element exhibit the oxidation state of +8?

Which element exhibits variable oxidation states ?

Why do transition elements show variable oxidation states? Write the name of a 3d-series element that exhibits maximum oxidation states.