The correct option is A completely
A strong electrolyte is a solute that completely, or almost completely, ionizes or dissociates in a solution. These ions are good conductors of electric current in the solution. Originally, a "strong electrolyte" was defined as a chemical that, when in aqueous solution, is a good conductor of electricity. Hence, it dissociates completely in the aqueous solution from the definition. Therefore, strong electrolytes dissociate completely in an aqueous solution.