Among the following  how many are amphoteric metal oxides 
$\mathrm{CO},{\mathrm{A\ell }}_2{\mathrm{O}}_3,\mathrm{BeO},{\mathrm{As}}_2{\mathrm{O}}_3,\mathrm{SnO},\mathrm{PbO},{\mathrm{SnO}}_2,{\mathrm{PbO}}_2{\mathrm{GeO}}_2$

Be, Al, Sn, Pb are metals and their oxides are amphoteric CO is neutral. As₂O₃ is amphoteric but As is metalloid GeO₂ is acidic.