This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardio thoracic surgery  , Subject name: Surgery
Thoracic outlet syndrome is primarily diagnosed by 
Select and explain. 
A. Clinical Evaluation, B. CT scan, C. MRI, D. Angiography
A: Clinical Evaluation
Answer: A: Clinical Evaluation 
Explanation: The initial presentation of thoracic outlet syndrome(eg.,in cervical rib)is dependent on whether the compression is primarily vascular,neurogenic or a combination of both.Vascular thoracic outlet syndrome can involve subclan aery or vein presenting with colour changes of affected upper extremity,claudication,or diffuse pain.Neurogenic syndrome involves brachial plexus presenting as sensory loss,pain or paraesthesia. Reference:Bailey & Love's sho practise of surgery,25th edition,pageno:895.