Which of the following statements regarding the property of hard water is/are correct ?
1. Temporary hardness of water is due to the presence of soluble magnesium and calcium hydrogen carbonate
2. Temporary harndness of water can be removed by boiling
3. Calgon's method is applied to remove temporary hardness of water
4. Permanent hardnes of water is removed by Clark's method
Select the correct answer using the code given below :
(a) 1 and 2 only
(b) 1, 2 and 3
(c) 3 and 4
(d) 2 only