Regarding Risky Behaviors and STDs, Which of the Following Statements

Regarding risky behaviors and STDs, which of the following statements is FALSE?

A) One cannot contract an STD through oral sex with an infected partner.
B) Having two or more sex partners or having sex with a person you know has had several partners increases one's risk of contracting an STD.
C) You cannot tell from a person's appearance if he or she is infected with an STD.
D) Many people would be surprised to learn that their partners have engaged in behavior that places them both at risk.