For a movable encroachment complaint, the EO can act on his own motion or based on a complaint from all EXCEPT:

Foundational Concept: Enforcement agencies require credible and actionable information to initiate formal proceedings, ensuring fairness and accountability in their actions.

• Correct Option (C) An anonymous tip: While anonymous tips can sometimes provide leads, enforcement officers typically cannot act solely on them for formal proceedings like issuing an EPO or taking direct action. The lack of a verifiable source makes it difficult to assess credibility or follow up, and could lead to frivolous complaints.
• Distractors (A) A department reference, (B) A whistle-blower, (D) Direction of the Authority: These are all legitimate and actionable sources. A department reference comes from an official channel. A whistle-blower, though often seeking anonymity, usually provides specific, verifiable information. Direction from the Authority is a direct mandate for action.