Final answer:
After an upper G.I. series with barium contrast, the patient should be advised to increase fluid intake to facilitate the elimination of barium and prevent constipation. While not one of the options, recommending a balanced diet high in fiber would also be beneficial for gastrointestinal health.
Step-by-step explanation:
The question pertains to the discharge instructions a nurse should provide to a patient after an upper gastrointestinal (G.I.) series with barium contrast. The most appropriate instruction from the provided options would be A. Increase fluid intake, as barium can cause constipation and increasing fluids can help facilitate the elimination of barium from the body. It is important for the patient to stay hydrated and promote normal bowel function following the procedure. While eating a balanced diet high in fiber is generally recommended for gastrointestinal health, it is not one of the provided options. However, including this as part of the post-procedure advice would be beneficial in normal circumstances. Taking anti-diarrheal medications or eating a low fiber diet is not routinely recommended after a barium contrast study unless specifically directed by a healthcare provider for particular clinical reasons.