Final answer:
Tina would most likely use a firewall to secure confidential company data, as it prevents unauthorized access by monitoring network traffic and providing a barrier between trusted and untrusted networks.
Step-by-step explanation:
As the head of the IT department responsible for securing confidential company data, Tina would most likely use a firewall to fulfill this responsibility. A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It establishes a barrier between a trusted internal network and untrusted external networks, such as the internet, to prevent unauthorized access to the company's sensitive data. While antivirus software helps protect against malware, and project management tools and video conferencing software serve different purposes, they do not specifically address the issue of limiting access to data to top-level management. The implementation of a firewall is key to ensuring that confidential information remains secure within the organizational hierarchy.