Explanation/Reference:
Explanation:
PCI DSS defines Dual Control as below:
Dual Control: Process of using two or more separate entities (usually persons) operating in concert to

protect sensitive functions or information. Both entities are equally responsible for the physical protection of materials involved in vulnerable transactions. No single person is permitted to access or use the materials (for example, the cryptographic key). For manual key generation, conveyance, loading, storage, and retrieval, dual control requires dividing knowledge of the key among the entities.
(See also Split Knowledge).
Split knowledge: Condition in which two or more entities separately have key components that

individually convey no knowledge of the resultant cryptographic key.
Incorrect Answers:
B: The term "need to know", when used by government and other organizations (particularly those related to the military), describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one has all the necessary official approvals (such as a security clearance) to access certain information, one would not be given access to such information, unless one has a specific need to know; that is, access to the information must be necessary for the conduct of one's official duties. As with most security mechanisms, the aim is to make it difficult for unauthorized access to occur, without inconveniencing legitimate access. Need-to-know also aims to discourage "browsing" of sensitive material by limiting access to the smallest possible number of people. This is not what is described in the question.
C: Separation of duties is the practice of dividing steps in a function among different individuals, so as to keep a single individual from being able to subvert the process. This is not what is described in the question.
D: Segregation of Duties address the splitting of various functions within a process to different users so that it will not create an opportunity for a single user to perform conflicting tasks. This is not what is described in the question.
References:
https://www.pcisecuritystandards.org/security_standards/glossary.php