Permanent hardness of water may be removed by addition of _______

[A] Sulphonate method
[B] Nitrate method
[C] Zeolite method
[D] None of these

(a) Which of the following ionic species could be responsible for hardness in a water supply: Ca²⁺, K⁺, Mg²⁺, Fe²⁺, Na⁺? (b) What properties of an ion determine whether it will contribute to water hardness?

can you determine the hardness of water with conductivity? or isnt that a good option, because conductivity is with all the ions?