All are true regarding brachial plexus injury,except:

• A. In klumpke's palsy,Horner's syndrome may be present on the ipsilateral side
• B. Histamine test is useful to differentiate between the preganglionic and postganglionic lesions
• C. Preganglionic lesions have a better prognosis than postganglionic lesions
• D. Erb's palsy causes paralysis of the abductors and external rotators of the shoulder.