3. Classification of elements and periodicity in properties — Chemistry STD 11 Science — Question

$(I)\,[Kr]\,5s^1$                                  $(II)\, [Rn]\,5f^{14}\,6d^1\,7s^2$ 

$(III)\,[Ar]\,3d^{10}\,4s^2\,4p^5$           $(IV)\,[Ar]\,3d^6\,4s^2$
Consider the following Statements

$(i)\, I$ shows variable oxidation State

$(ii)\, II$ is a $d-block$ element
$(iii)$ The compound formed between $I$ and $III$ is covalent
$(iv)\,IV$ shows single oxidation state
Which Statement is True $(T)$ or False $(F)$?