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: Pediatrics
A child with fever and sore throat developed acute cervical lymphadenopathy most likely investigation to be done is : 
Select and explain. 
A. Open biopsy of node, B. Radical neck dissection, C. Neck X–ray, D. Complete hemogram
D: Complete hemogram
Answer: D: Complete hemogram 
Explanation: Cervical lymphadenopathy with signs of infection such as fever and sore throat points towards any infectious etiology.
In this case the most likely investigation to be done should be complete hemogram.
Complete hemogram can provide useful datas for diagnosis of :


Pyogeizic infections.
Viruses such as EBV CMV & HIV.
Leukemias (acute or chronic).

Biopsy should be done if the patients history and physical findings suggest malignancy. These features are :

Solitary, hard non-tender cervical nodes in an older patient.
Neck X-ray does not provide much information except for giving some idea about swollen soft tissues of neck.
Radical neck dissection is absurd option.