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: Radiology
First complication after radiotherapy is: 
Select and explain. 
A. Mucositis, B. Candidiasis, C. Alopecia, D. Xerostomia
A: Mucositis
Answer: A: Mucositis 
Explanation: None