Solution:
Concept- Alkaline earth metals have more basic oxides than do alkali metals. The basic character gets stronger as one descends the alkali metals or alkaline earth metals group.The fundamental character's ascending order is as follows:
Basic oxide compounds are created when metals combine with oxygen to produce compounds. The position of the metal in the periodic table directly affects how basic these oxides are. The electronegativity of the elements increases from left to right in a period. Thus, the basic character of metal oxides decreases from left to right. On the other hand, the effective nuclear charge on the atoms falls as we go from top to bottom in a group. As a result, the basic character of metal oxides decreases as we move from top to bottom in a group.
Hence, option 3 is correct.