Hyponatremia is defined as blood sodium levels below 130-135 mmol per liter
Which of the following is the correct definition of hyponatremia?

A) Blood sodium levels above 130-135 mmol per liter
B) Blood sodium levels below 130-135 mmol per liter
C) Blood sodium levels between 130-135 mmol per liter
D) Blood sodium levels exactly at 130-135 mmol per liter