Which of the following is an open source of intelligence?

An open source of intelligence refers to information that is publicly available and can be collected and analyzed for various purposes, including law enforcement and investigations. Public records, third-party companies, and social media all represent sources of open intelligence because they can be accessed by the public without special permissions or restrictions.

Public records, such as court documents, property records, and other governmental databases, provide valuable insights that can aid in investigations and help build a larger understanding of a situation or individual.

Third-party companies, especially those that compile data from various public sources, can offer unique insights and analytics, often aggregating information that might otherwise be difficult to obtain through piecemeal efforts. They utilize publicly available information to offer critical data that can assist in various fields, including security and law enforcement.

Social media platforms are another significant source of open intelligence. These platforms provide real-time data and interactions that are accessible to anyone with internet access, offering insight into individuals' behaviors, networks, and public sentiments.

By encompassing all of these sources, the correct answer underscores the comprehensive nature of open-source intelligence and its utility in various contexts, particularly in human trafficking investigations where leveraging publicly available information can be crucial in identifying and combating criminal activities.