The property of the alkaline earth metals that increases with their atomic number is

Select the correct statement from the following.

Assertion $(A)$: $MgO$,$CaO$,$SrO$,and $BaO$ are insoluble in water.
Reason $(R)$: In aqueous medium,the basic strength of $MgO$,$CaO$,$SrO$,and $BaO$ increases with an increase in the atomic number of the metal.
The correct option among the following is:

The most stable carbonate is

Which is used to reduce the acidity of soil?

Which colour is developed in the solution when alkaline earth metals are dissolved in liquid ammonia?