Imagine you are writing a research paper on social networking sites. Which of the following thesis statements would be the most effective?

A. Social networking sites have become incredibly popular in recent years and have millions of members. Many of these sites are now working on improving their privacy measures.
B. Social networking sites are popular online tools that help people connect on topics of interest. One of the challenges social networks are facing today is privacy protection.
C. Millions of people joined social networking sites to share pictures and videos with their friends. However, many people wish their private images and thoughts would be treated more securely.

B. Social networking sites are popular online tools that help people connect on topics of interest. One of the challenges social networks are facing today is privacy protection.

This thesis statement is the most effective as it clearly states the topic of the research paper (social networking sites and privacy protection) and sets up for a discussion on the challenges faced by social networks in terms of privacy.