Group 2 sulfates exhibit solubility in water Steps:

• Apply standard solubility rules: group 2 chlorides and hydroxides are generally soluble, but carbonates and some hydroxides are not; sulfates are mostly soluble.
• Check option A: BaCl₂ soluble, but CaCO₃ (carbonate) and Mg(OH)₂ (hydroxide) insoluble.
• Check option B: Ba(OH)₂ and Ca(OH)₂ soluble, but SrCO₃ (carbonate) insoluble.
• Check option C: BaSO₄, CaSO₄, MgSO₄ all group 2 sulfates, soluble per rules.
• Check option D: BaSO₄ and CaSO₄ soluble, but Mg(OH)₂ insoluble.

Why C is correct:

• Solubility rules state sulfates of group 2 metals (Mg²⁺, Ca²⁺, Ba²⁺) dissolve in water, forming aqueous solutions.

Why the others are wrong:

• A: Contains insoluble CaCO₃ (carbonates of group 2 insoluble) and Mg(OH)₂ (sparingly soluble hydroxide).
• B: Contains insoluble SrCO₃ (group 2 carbonates insoluble).
• D: Contains insoluble Mg(OH)₂ (group 2 hydroxide with low solubility).

Final answer: C