Detailed Explanation:

Rationale for Correct Answer: A major red flag of a Ponzi scheme is when the promoter has custody and control over investor funds with little to no independent oversight. This centralization allows them to use new investor money to pay old investors while concealing losses.

Analysis of Incorrect Options:

A – Ponzi operators usually pressure investors to reinvest, not take payouts, to keep funds circulating.

C – Schemes often involve overly complex or secretive strategies, not simple ones.

D – Realistic fluctuations based on markets suggest legitimate investing, not a Ponzi scheme (which typically reports steady, unrealistic returns).

Key Concept: Ponzi schemes rely on lack of oversight, unrealistic returns, and control of funds by promoters.