This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: mycology, Subject name: Microbiology
A patient with acute leukaemia is admitted with febrile neutropenia. On day four of being treated with broad-spectrum antibiotics, his fever increases. X-ray chest shows bilateral fluffy infiltrates. Which of the following should be the most appropriate next step in the management 
Select and explain. 
A. Add antiviral therapy, B. Add antifungal therapy, C. Add cotrimoxazole, D. Continue chemotheraphy
B: Add antifungal therapy
Answer: B: Add antifungal therapy 
Explanation: Cotrimoxazole is an antibiotic. As the patient is immunocompromised, most probable oppounistic infection is a fungal infection. And X-Ray shows fluffy infiltrates is suggestive of fungal infection. So antifungals are to be added. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition