Final answer:
The safe rate of sodium replacement for hyponatremic patients is gradual correction.
Step-by-step explanation:
For hyponatremic patients, the safe rate of sodium replacement is option B: gradual correction. Rapid infusion (option A) can cause a rapid increase in sodium levels, which may have harmful effects on the brain and nervous system. Bolus administration (option C) and intermittent doses (option D) also carry the risk of sodium fluctuations that can be detrimental to the patient's health.