<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 36-year-old woman presents to the emergency department with a 2-day history of conjunctivitis, sensitivity to bright light, and decreased visual acuity. She denies a history of ocular trauma. She wears contact lenses and thought that the contact lenses may be the cause of the symptoms, although she has always used proper hygiene. Fluorescein staining showed a corneal dendritic branching ulcer with terminal bulbs that stained with rose bengal. Giemsa staining revealed multinucleated giant cells. What is the most likely causative agent?? A: Herpes simplex virus HSV-1 , B: Varicella zoster virus, C: Acanthamoeba, D: Candida albicans, E: Pseudomonas ,  <response>: This is a question about identifying the most likely causative agent for a patients symptoms of conjunctivitis, light sensitivity, decreased visual acuity, and corneal dendritic ulcer. The key findings are a corneal dendritic ulcer that stains with rose bengal and contains multinucleated giant cells on Giemsa staining. A dendritic corneal ulcer with terminal bulbs is classic for herpes simplex virus HSV infection. HSV dendritic ulcers stain positively with rose bengal. Multinucleated giant cells are also characteristic of HSV infection. Varicella zoster virus can cause herpetic keratitis, but dendritic ulcers are less common compared to HSV. Acanthamoeba and Candida can cause keratitis in contact lens wearers, but not dendritic ulcers. Pseudomonas is associated with contact lens-related keratitis, but causes more infiltrativeinflammatory appearance rather than dendritic ulcers.Based on the clinical presentation and staining findings, the most likely causative agent is HSV-1.A: Herpes simplex virus HSV-1 