The correct sequence of increasing the basic nature of the following oxides is: 

1. ${\mathrm{Al}}_2{\mathrm{O}}_3<\mathrm{MgO}<{\mathrm{Na}}_2\mathrm{O}<{\mathrm{K}}_2\mathrm{O}$

2. $\mathrm{MgO}<{\mathrm{K}}_2\mathrm{O}<{\mathrm{Al}}_2{\mathrm{O}}_3<{\mathrm{Na}}_2\mathrm{O}$

3. ${\mathrm{Na}}_2\mathrm{O}<{\mathrm{K}}_2\mathrm{O}<\mathrm{MgO}<{\mathrm{Al}}_2{\mathrm{O}}_3$

4. ${\mathrm{K}}_2\mathrm{O}<{\mathrm{Na}}_2\mathrm{O}<{\mathrm{Al}}_2{\mathrm{O}}_3<\mathrm{MgO}$

Among \(\mathrm{Al}_{2} \mathrm{O}_{3}, \mathrm{SiO}_{2}, \mathrm{P}_{2} \mathrm{O}_{3}\) and \(\mathrm{SO}_{2}\) the correct order of acid strength is:

1. \(\mathrm{SO}_{2}<\mathrm{P}_{2} \mathrm{O}_{3}<\mathrm{SiO}_{2}<\mathrm{Al}_{2} \mathrm{O}_{3}\)

2. \(\mathrm{SiO}_{2}<\mathrm{SO}_{2}<\mathrm{Al}_{2} \mathrm{O}_{3}<\mathrm{P}_{2} \mathrm{O}_{3}\)

3. \(\mathrm{Al}_{2} \mathrm{O}_{3}<\mathrm{SiO}_{2}<\mathrm{SO}_{2}<\mathrm{P}_{2} \mathrm{O}_{3}\)

4. \(\mathrm{Al}_{2} \mathrm{O}_{3}<\mathrm{SiO}_{2}<\mathrm{P}_{2} \mathrm{O}_{3}<\mathrm{SO}_{2}\)

Consider the following compounds:

BeO, BaO, Be(OH)₂, Sr(OH)₂

The amphoteric compound(s) are: