I think the correct answer would be to increase. As salt is being dissolved in water, it dissociates into corresponding ions which would make conductivity of the solution more higher than pure water since charge particles are already present. Hope this helps.
The conductivity of the resulting solution will increase.
Explanation:
The conductivity of the solution obtained by adding sodium hydroxide in water will increase as compared to pure water due to complete dissociation of sodium hydroxide into sodium ion and hydroxide ions. The conductivity increases on increase in number of ions in a solution.
