To be eligible to donate blood, women must have a minimum hemoglobin level of:

The correct answer is 12.5 g/dL. This hemoglobin level is a standard threshold set to ensure that blood donation is safe for the donor. The minimum hemoglobin level is established to minimize the risk of anemia in donors after they donate blood.

Women generally have lower hemoglobin levels compared to men due to physiological differences, which makes it crucial to set an appropriate threshold that accounts for these variations without putting women at risk of low iron levels or anemia post-donation. A hemoglobin level of 12.5 g/dL ensures that the women donating have adequate blood levels to remain healthy after the procedure, thus promoting overall safety in blood donation practices.

In comparison, lower hemoglobin thresholds, such as those below 12.5 g/dL, could expose women to increased risks of health complications, which is why the standard is set at or above this measurement. Other levels listed in the choices do not align with the established safety protocols set forth by blood donation guidelines.