If left untreated, can result in death. a. gonorrhea b. syphilis c. chlamydia d. herpes

The correct answer is b. Syphilis.

Syphilis is a type of sexually transmitted disease and the causative agent is bacteria called Treponema pallidum. There are four stages of syphilis: primary, secondary, latent and tertiary. It is a highly contagious disease.

The disease starts to get spread from sores and the pregnant women can pass the disease to the child and can cause abnormalities or even death of the child. If syphilis is untreated till the tertiary phase, it can lead to problems in heart, blindness, deafness, brain, nerves leading to paralysis and even death.