Why do the D blocks elements show different Oxidation State​

These elements show variable oxidation state because their valence electrons in two different sets of orbitals, that is (n-1)d and ns. The energy difference between these orbitals is very less, so both the energy levels can be used for bond formation.

Mark me as brainliest pls pls pls pls pls

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current