In a locality, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory:
1. Sodium sulphate
2. Calcium sulphate
3. Magnesium chloride
4. Sodium chloride
5. Calcium chloride
6. Potassiu msulphate
Which of the above salts may be dissolved in water to obtain hard water for the experiment
(A) 2, 3 and 5 (B) 1, 2 and 5
(C) 1, 2, 4 and 6 (D) 3 and 5 only.
