Solubility of M(OH)2 is in order
Be(OH)2>Mg(OH)2>Ba(OH)2
Ba(OH)2<Be(OH)2<Mg(OH)2
Be(OH)2<Mg(OH)2<Ba(OH)2
Mg(OH)2<Be(OH)2<Ba(OH)2
Solubility of hydroxides increasing moving down the IIA group.