In which age group is the risk of $STDs$ highest?

Syphilis is an infectious bacterial disease caused by $Treponema\ pallidum$ with $3$ stages:
$(A)$ Infectious painless ulcers on the genitals $\quad(i)$ First
$(B)$ Blindness, heart trouble, aortic impairment $\quad(ii)$ Second
$(C)$ Skin lesions, hair loss, swollen joints $\quad(iii)$ Third
Which of the following is the correct match between the symptoms and stage?

Which of the following sexually transmitted diseases is not completely curable?

From the sexually transmitted diseases mentioned below,identify the one which does not specifically affect the sex organs.

Which pathogen causes genital warts,a type of $STD$ in humans?

Which of the following diseases is not sexually transmitted?