Blue.

 Due Diligence in High-Corruption Risk Transactions:

When operating in high-risk environments, enhanced due diligence is critical. This includes evaluating payment methods, transaction patterns, and the customer ' s reputation.

 Why A is Correct:

Analyzing purchasing patterns and payment methods helps identify red flags such as unusual payment terms or volumes inconsistent with Green’s business profile.

 Why Other Options are Incorrect:

B: Due diligence is necessary regardless of payment terms.

C: Enhanced due diligence for high-risk countries does not constitute discrimination.

D: Ignoring due diligence poses significant compliance and reputational risks.

 References:

ACFE guidance on due diligence and anti-corruption practices in global commerce​​.