Final answer:
Digestive complications include diarrhea and the use of antacids as treatments, but probiotics are used to prevent or alleviate these issues. Diarrhea can occur due to an imbalance in gut microbiota, often associated with C. difficile infection after antibiotic use.
Step-by-step explanation:
Digestive complications include various symptoms and conditions related to the gastrointestinal (GI) tract. Among these, diarrhea can be a common complication, particularly when the balance of the gut microbiota is disrupted, as seen in antibiotic-associated diarrhea caused by Clostridium difficile. This pathogen can overgrow when other normal bacteria are eliminated due to antibiotic use, leading to severe diarrhea. In contrast to diarrhea, which is a digestive complication, probiotics and antacids serve as interventions; probiotics can help restore intestinal microbial balance, and antacids can relieve symptoms caused by stomach acidity.
Therefore, digestive complications include both diarrhea (a) and the use of antacids (c) as treatments, making 'd) both a and c' the correct answer to the question. Probiotics, on the other hand, are used to help prevent or alleviate these complications rather than being a complication themselves.