First Principles Thinking: reasonableness and influence are the real tests
C is correct. Standard I(B) does not ban all outside compensation. The question is whether the amount or context could reasonably be expected to influence the member's objectivity.
A is tempting because zero-tolerance rules seem safer, but the curriculum does not impose a blanket ban on modest, legitimate payments for services.
B fails because a larger payment can increase, not reduce, the risk to objectivity.