The electronic configuration of four elements are :
(I)   [Kr]5s¹
(II)  [Rn]5f¹⁴6d¹7s²
(III) [Ar]3d¹⁰4s²4p⁵
(IV) [Ar]3d⁶4s²

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)?

1. FTFF
2. FTFT
3. FFTF
4. FFFF