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
A male patient presents with patchy loss of hair on scalp, eyebrows and beard. He also gives istory of rapid graying of hair in a few areas. The likely diagnosis is- 
Select and explain. 
A. Alopecia areata, B. Anagen effluvium, C. Telogen effluvium, D. Androgenic alopecia
A: Alopecia areata
Answer: A: Alopecia areata 
Explanation: History of patchy hair loss with retaining of grey hairs is alopecia areata. other options anagaen effluvium, telogen effluvium are diffuse hair loss. androgenetic alopecia is paterened hair loss or male pattern baldness which involve fronto temporal receding. Ref Harrison20th edition pg 1230