Detailed Answer
Answer (B) is correct. Segregation of duties and other control procedures serve to prevent or detect a fraud committed by an employee acting alone. One employee may not have the ability to engage in wrongdoing or may be subject to detection by other employees in the course of performing their assigned duties. However, collusion may circumvent controls. For example, comparison of recorded accountability with assets may fail to detect fraud if persons having custody of assets collude with record keepers.