A patient presents with foreign body sensation in eye and swollen knee joint after a leisure trip. Which of the following is the most probable diagnosis?

As the patient in the question has developed ahritis following a recent travel, it could be a reactive ahritis secondary to organisms endemic in the zone of travel. Along with this, patient is showing features of conjunctivitis indicating a diagnosis of Reiter's syndrome. Reactive ahritis (Reiter's syndrome) consists of conjunctivitis, urethritis (or cervicitis in female patients), ahritis, and characteristic mucocutaneous lesions. Ref: Harrison's Internal Medicine, 18th Edition, Chapter 176