Final answer:
Logan will likely prescribe an antifungal shampoo for the pet pig's ringworm, because ringworm is a fungal infection and antifungal agents are the appropriate treatment. The correct answer is option: D. an antifungal shampoo to bathe in.
Step-by-step explanation:
Ringworm is a fungal infection characterized by red, itchy circular patches on the skin, and it can be identified with a Wood's lamp test, which makes the infection fluoresce. Logan, the veterinarian, would most likely prescribe an antifungal shampoo for the pet pig to bathe in, because ringworm is caused by a fungus, and antifungal treatments are used to combat fungal infections.
While oral antibiotics are used for bacterial infections, ringworm would not be treated with antibiotics since it is not a bacterial infection. Corticosteroids are used to reduce inflammation but do not address the fungal cause of ringworm, and vaccines are preventive measures and do not treat existing infections.