Answer:
Katherine's opportunity cost is the cost of getting to the lecture event itself plus the reduction in her physics exam grade by not studying tonight. True
Step-by-step explanation:
Opportunity cost is the cost of foregoing a benefit or incurring loss due to opting an alternative which is next beneficial . Here Katherine is losing in terms of grades in her exam to take the benefit of listening to the lecture , So loss to her grade is the opportunity cost of attending to the lecture and getting benefited.