Final answer:
The safest medication for treating postpartum hemorrhage is oxytocin.
Step-by-step explanation:
The safest medication for Ashley if a second drug is needed to treat postpartum hemorrhage is a) Oxytocin. Oxytocin is a hormone that helps stimulate contractions in the uterus, which can help control bleeding after childbirth. It is commonly used for the prevention and treatment of postpartum hemorrhage. Other options such as b) Misoprostol, c) Methylergonovine, and d) Carboprost may also be used, but they have more potential side effects and are typically considered second-line treatments.