Permanent hardness of water due to sulphate of metals can be destroyed by the use of ___ ?

✅ A. Blue moon

✅ C. yellow dwarf

✅ C. protein

✅ D. Zoonosis

✅ D. To keep the Center of gravity always above vertically above the rope

✅ B. Acetone

✅ C. Silver

✅ C. 79