S Block Elements

Assertion (A) $\mathrm{MgO}, \mathrm{CaO}, \mathrm{SrO}$ and BaO are insoluble in water.

Reason ( R ) In aqueous medium the basic strength of $\mathrm{MgO}, \mathrm{CaO}, \mathrm{SrO}$ and BaO increases with increase in the atomic number of metal.

The correct option among the following is