Explanation:
A control or countermeasure which does not overlap in its performance with another control or countermeasure is considered as distinct. Hence the separation of controls in the production environment rather than the separation in the design and implementation of the risk refers to distinct.
Incorrect Answers:
A: Trusted source refers to the commitment of the people designing, implementing, and maintenance of the control towards the security policy.
B: Secure controls refers to the activities ability to protect from exploitation or attack.
D: The separation in design, implementation, and maintenance of controls or countermeasures are refer to as independent. Hence this answer is not valid.