Final answer:
The correct ratio format to express the dosage of an injectable solution containing 250 mg in each 0.3 ml is A) 250 mg / 0.3 ml.
Step-by-step explanation:
The question asks us to express the dosage using the preferred ratio format, where the injectable solution contains 250 mg in each 0.3 ml. The correct way to express this dosage in the ratio format would be A) 250 mg / 0.3 ml. This represents the concentration of the medication in the injectable solution, with 250 milligrams of medication contained within 0.3 milliliters of solution.