$PbF_4$ and $PbCl_4$ exist,while $PbBr_4$ and $PbI_4$ do not exist. This is due to:

• A
  Large size of $Br$ and $I$
• B
  Strong oxidizing nature of $Pb^{4+}$
• C
  Strong reducing nature of $Pb^{4+}$
• D
  Low electronegativity of $Br^-$ and $I^-$