A fundamental principle in designing a computer forensics lab is maintaining strict physical security to protect evidence integrity and the chain of custody. A single, controlled point of entry and exit is a critical design element to achieve this. This design simplifies access control, allowing for effective monitoring and logging of all individuals entering or leaving the secure area. Multiple entrances increase the complexity and cost of security monitoring and introduce additional risks of unauthorized access or evidence tampering, which is contrary to established forensic best practices.

A. Three: Having three exits would create significant security vulnerabilities, making it extremely difficult to monitor and control access effectively, thereby compromising the integrity of the forensic environment.
C. Two: While a second exit may be required by fire codes for larger spaces, it is not the ideal design from a security perspective. The primary design should feature one main access point, with any additional exits designated for emergency use only and equipped with alarms.
D. Four: This option represents an unacceptable level of security risk for a facility handling sensitive evidence. Managing and securing four separate exits would be impractical and counterproductive to forensic principles.

1. National Institute of Justice (NIJ), U.S. Department of Justice. (2004). Forensic Examination of Digital Evidence: A Guide for Law Enforcement. NCJ 199408. In Chapter 3, "Setting Up a Computer Forensics Laboratory," the guide emphasizes strict laboratory security, stating, "Limit access to the laboratory to authorized individuals. Maintain a log of all persons who enter and exit the laboratory" (p. 13). A single entry/exit point is the most effective physical control to enforce this requirement.

2. Scientific Working Group on Digital Evidence (SWGDE). (2017). SWGDE Best Practices for Computer Forensics v3.1. Section 4.2, "Facility," states, "Access to the digital evidence examination and storage areas shall be limited to authorized personnel." The principle of limiting access is most effectively implemented by minimizing the number of access points to one.

3. Casey, E. (2011). Digital Evidence and Computer Crime: Forensic Science, Computers, and the Internet (3rd ed.). Academic Press. In Chapter 6, "Digital Forensics Laboratory," the text discusses the importance of physical security and access controls. It notes that a secure lab environment must have controls to "restrict access to the lab and evidence storage areas," a principle best served by a single, monitored entrance (Section 6.3.1).