Pong-tai is a 12-month-old child who is being treated with amoxicillin for acute otitis media. His parents call the clinic and say he has developed diarrhea. The appropriate action would be to:

a. Advise the parents that some diarrhea is normal with amoxicillin and recommend probiotics daily.
b. Change the antibiotic to one that is less of a gastrointestinal irritant.
c. Order stool cultures for suspected viral pathogens not treated by the amoxicillin.
d. Recommend increased fluids and fiber in his diet.