This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
Drug used in actinic keratosis is: 
Select and explain. 
A. Methotrexate, B. Topical 5 FU, C. Topical mechlorethamine, D. Topical steroids
B: Topical 5 FU
Answer: B: Topical 5 FU 
Explanation: The US Food and Drug Administration (FDA) has approved five medications for the treatment of actinic keratoses. These are topical 5-fluorouracil (5-FU), 5% and 3.75% imiquimod cream, topical diclofenac gel, ingenol mebutate, and photodynamic therapy with topical delta-aminolevulinic acid ESSENTIALS OF MEDICAL PHARMACOLOGY SIXTH EDITION -KD TRIPATHI Page:824