This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
Investigation of choice for dysphagia for solids - 
Select and explain. 
A. Barium swallow, B. Endoscopy, C. X ray chest, D. CT scan
B: Endoscopy
Answer: B: Endoscopy 
Explanation: Dysphagia for solid food may be due to mechanical causes like: Carcinoma Peptic and other benign strictures Lower oesophagal ring The investigation of choice in mechanical obstruction is endoscopy Barium swallow is the first investigation Ref : CMDT 2005, p 547