Final answer:
The nurse should respect the parents' refusal based on religious beliefs while also informing them of the potential risks. Administering the transfusion without consent or seeking a court order are generally not the initial steps to take.
Step-by-step explanation:
When a nurse is caring for a client prescribed a blood transfusion and the parents refuse due to religious beliefs, the nurse should respect the religious beliefs and withhold the transfusion (Option A). Parents can legally provide consent on behalf of their children, as children are not seen as competent to provide consent for themselves. However, informing the parents of the potential harm that may result from refusal is also important (Option D). The nurse should not administer the blood transfusion without parental consent (Option B), and obtaining a court order (Option C) may be considered in some jurisdictions if the child's life is in imminent danger and there is no other way to protect the child's health or life.
It is also essential to match the ABO blood type to prevent a possible hemolytic transfusion reaction (HTR), which can be a serious and potentially lethal complication.