The correct option is
C a(ii), b(iv), c(v), d(iii)
a) Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum. It causes sores, blisters, ulcers on the genitals, anus, or mouth.
b) Genital herpes is a sexually transmitted disease. It is caused by herpes simplex virus type 1 (HSV-1). It causes painful blisters.
c) Genital warts is a sexually transmitted infection caused by human papillomavirus (HPV). Symptoms include soft growths that occur on the genitals.
d) Hepatitis-B is an infection of the liver. It is caused by the hepatitis B virus (HBV). HBV is a double-stranded DNA virus.
Thus, the correct answer is option C.