A 24-year-old man presents with complaints of increasing drainage from both eyes associated with mild discomfort for the past day. He denies severe eye pain or blurring of his vision. He also complains of dysuria and urethral discharge. He is sexually active and does not regularly use protection. On examination, his visual acuity is 20/20 in both eyes. There is profuse purulent discharge as well as marked chemosis, lid swelling, and tender preauricular adenopathy. Which of the following is the most appropriate diagnostic evaluation?
A. Direct Fluorescent antibody testing
B. Fluorescent treponemal antibody absorption test
C. Gram Stain
D. Tzanck Smear