I believe the answer you are looking for is the excretory system.
Chancre
The first sign of syphilis is a small sore, called a chancre (SHANG-kur). The sore appears at the spot where the bacteria entered your body. While most people infected with syphilis develop only one chancre, some people develop several of them. The chancre usually develops about three weeks after exposure.
C is the correct answer, because advertisers don't want people to see the bad sides of their product. They only want to display the "positive" effects of purchasing their product.
Hope I helped!
