Final answer:
The Private Security and Investigative Services Act, 2005 regulates the security industry in Ontario, setting standards for licensing, training, and conduct of security guards and private investigators.
Step-by-step explanation:
The correct answer to the question of which entity regulates the security industry in Ontario is B) The Private Security and Investigative Services Act, 2005. This act establishes a regulatory framework for the private security and investigative services industry in Ontario, which includes the licensing of security guards, private investigators, and the agencies that employ them. The act ensures that individuals and agencies comply with training and conduct standards, maintain public trust, and increase accountability within the industry.