What is true about the privacy risks of social media?

A、Our personal information may be leaked by some of friends, colleagues and companies we interact with on social media.
B、Identity thieves tend to gather personal information from the information available on the social media.
C、It is easy for malicious people to track our whereabouts, if we post the location in social media.

D、Posting your full name, social security number, address, phone number, or account numbers in social media is risky.