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: Gynaecology & Obstetrics
A lady with CA ovary in follow up with raised CA 125 level, Next step: 
Select and explain. 
A. CT, B. PET, C. MRI, D. Clinical exam and serial follow up of CA 125
B: PET
Answer: B: PET 
Explanation: None