###Rationale: Onabotilinum toxin A has recently been approved to prevent a headache in adult patients with chronic migraine.

###Answer: OPTION B IS CORRECT.
###Question: Onabotulinum toxin A can be used for the treatment of:
###Options:
A. Cervical dystonia.
B. Chronic migraine.
C. Blepharospasm.
D. Strabismus.
