The prime targets for skimming schemes, which are hard to monitor and predict such as...

Detailed Explanation:

Rationale for Correct Answer: Irregular, low-value, or unpredictable revenue sources such as parking fees, late charges, or vending machine sales are prime skimming targets. Because they are difficult to estimate or reconcile precisely, theft of these funds is less likely to be detected quickly.

Analysis of Incorrect Options:

B. Recorded sales – These are already in the books and easier to reconcile.

C. Internal audits – A control mechanism, not a target.

D. Register manipulations – A method, not the revenue source itself.

Key Concept: Vulnerable revenue streams as skimming targets.