Ans. is 'c' i.e., Tertiary Syphilis* Incubation period of syphilis is 10-90 days (median 21 days), following which natural infection passess through three stages : Primary, secondary and tertiary.Primary syphilis* Lesion of primary syphilis is chancre (Hard chancre). It occurs at the site of entery of spirochete. Primary chancre is well defined punched out ulcer which has following characteristics : -1) Single lesion2) Painless3) Avascular (non-bleeding)4) Firm inducation5) Usually superficial (but may be deep)6) Well circumscribed with elevated round or oval edges7) Cartilagenous consistency8) Lymphadenopathy which is painless, firm and nonsuppurative.* Sites of involvement are penis in heterosexual males; rectum, anal canal, mouth in homosexual males; and cervix and labia in females.Secondary syphilis* Secondary syphilis presents with : -1) Most common manifestation is rash. Rash is usually bilateral symmetrical macule or maculopapular which occurs on palms & soles. The macule is non-pruritic and asymptomatic. Other lesions may be papules or papulo-squamous.2) Generalized non- tender ymphadenopathy.3) Condyloma lata - It is the most infectious lesion of syphilis. These are large pink or gray-white papules in warm, moist, intertriginous areas especially perianal, vulva and scrotum.4) Mucous patches : - Superficial mucosal erosions in lips, oral mucosa, tongue pharynx, vulva, vagina, glans penis, inner prepuce.5) Constitutional symptoms : - Sore throat, fever, weight loss, malaise, anorexia, headache.6) Moath eaten alopecia - It is patchy alopecia.7) Buschke ollendraff sign : Deep dermal tenderness on pressure* Spirochetes are abundant in the lesions and consequently the patient is most infectious during secondary stage (especially condyloma lata lesions).Complications of secondary syphilis:* Acute meningitis* GIT - Gastritis, proctitis, recto sigmoid mass, Hepatosplenomegaly* Nephropathy - Proteinuria.* Eye - Anterior uveitis, optic neuritis, retinitis pigmentosa* Skeletal - Arthritis, periostitisSecondary syphilis is not a vesiculo-bullous disorder - Vesicle or bullae are not seen in secondary syphilis on the other hand congenital syphilis is a vesiculo-bullous disorder - vesicle/bullae are seen in congenital syphilis.Latent syphilis* It is described as asymptomatic stage in a patient with definite history revealing the contraction of the disease, but exhibiting only a reactive serology (positive serological tests). It occurs between secondary and tertiary stage. It can be divided into two types : -A) Early latent or relapsing syphilis: - It occurs during first 2 year. Chancre may recurve in its original place - Chancre redux (Note - Chancre redux is due to relapse of original infection, not due to reinfection).B) Late latent or non-relapsing syphilis : - It occurs after 2 years and there is no relapse.* Latent syphilis may either have spontaneous cure or progress to tertiary syphilis or presist as latent syphilis.Tertiary syphilis* Tertiary syphilis may present: -1) Cardiovascular syphilis : - Aortitis, aortic regurgitation, saccular aneurysm, linear calcification in ascending aorta.2) Asymptomatic neurosyphilis3) Symptomatic neurosyphilis: -Meningeal, meningeovascular, parenchymatous, Tabes dorsalis, General PARESIS.4) Late benign syphilis (Gumma): - There are solitary lesions on skin, Skeletal system, the mouth and upper respiratory tract. Gumma are non-infectious and spirochetes are very difficult to demonstrate in this lesion.