This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of skin, Subject name: Dental
Exclamation mark alopecia is a feature of - 
Select and explain. 
A. Telogen effluvium, B. Androgenic alopecia, C. Alopecia aerata, D. Alopecia mucinosa
C: Alopecia aerata
Answer: C: Alopecia aerata 
Explanation: Sho,1-2 mm fractured hairs can frequently be seen at the active margins of alopecia areata. These hairs are described as exclamation mark hairs because these characteristic hairs fracture at their distal end and taper proximally to a pencil point giving them appearance of an exclamation mark Ref Harrison20th edition pg 1233