- The correct answer is Gram-negative diplococci because Neisseria gonorrhoeae, the causative organism of gonorrhea, appears as kidney-shaped gram-negative diplococci on Gram stain of urethral discharge.
- This characteristic morphology helps in rapid and presumptive diagnosis, especially in symptomatic men. Other options represent different organisms unrelated to gonorrhea.

Reference: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, 9th Edition, Volume 2, Chapter 161