This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
A patient of acute leukemia 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 managment - 
Select and explain. 
A. Add antiviral therapy, B. Add antifungal therapy, C. Add cotrimoxazole, D. Continue chemotherapy
C: Add cotrimoxazole
Answer: C: Add cotrimoxazole 
Explanation: None