B. Points are awarded at the maximum threshold: This is incorrect. The RP point is awarded for achieving the credit, regardless of the specific threshold met, as long as the minimum is achieved.
C. Points are awarded when the maximum threshold has been exceeded: This is incorrect. LEED awards points for meeting defined thresholds, not for exceeding them, and the RP credit is tied to simply achieving the base credit.
D. Points are awarded at particular levels of achievement: This is too vague. The rule is specific: the bonus point is awarded upon meeting the first level of achievement (the minimum threshold) for the designated credit.