A 17 year-old female with neurofibromatosis type 1 is seen in the outpatient clinic. She has been referred because of attacks of right-sided weakness that happen during hyperventilation or exercise. An MRI brain is obtained and T2-FLAIR images are shown below. Based on the findings of the MRI, she is referred for digital subtraction angiography of the carotid and intracranial arteries. What is it most likely to show?
A. Arteriovenous malformation
B. 'Puff of smoke' appearance
C. Segmental dilatation and stenosis of the left MCA and its branches
D. Stenosis of the left common carotid artery at its origin
E. String of beads appearance of the left MCA