(A) : BeO and Al₂O₃ are amphoteric.
(R) : Be and Al are made passive by HNO₃.

BeO and Al₂O₃ are amphoteric in nature.

The oxides of both Be [BeO] and Al[Al₂O₃] are amphoteric and hence they dissolve in NaOH solution as well as in HCl
BeO + 2HCl → BeCl₂ + H₂O
 

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O
${\mathrm{Al}}_2{\mathrm{O}}_3+2\mathrm{NaOH}\to 2{\mathrm{NaAlO}}_2+{\mathrm{H}}_2\mathrm{O}$

Be and Al become passive (resistant) on reaction with concentrated nitric acid due to formation of protective oxide layer on the surface of the Be and Al metals.