According to the BABOK® Guide, opportunity cost is the value of the next best alternative that is forgone as a result of making a decision. In this case, the opportunity cost of choosing the second project for $565,000 is the value of the first project that is not chosen, which is $375,000. This means that the organization is giving up the potential benefit of $375,000 by selecting the second project over the first one. References: BABOK® Guide, page 32; Business Analysis Expert Certification, CCBA® | IIBA®, section “What Should I know to be CCBA Certified?”