Final answer:
The question about the point at which crew can give complimentary service during a delay is related to airline policies and cannot be answered accurately without specific information. The solution fragments do not contain information on these policies, instead discussing customer arrival rates and waiting times, which may suggest a business or operations management context.
Step-by-step explanation:
The question relates to policies regarding complimentary service on board a flight in the event of a delay. The provided solution segments, however, do not directly answer the question about the specific time at which crew can give complimentary service.
These segments discuss customer arrival rates and waiting times, which are indicative of a problem related to queuing theory or probabilities, common topics in operations management or business studies. Nonetheless, without additional context about the specific airline's policies or industry standards, it's not possible to determine the correct answer from A) After 30 minutes, B) After 45 minutes, C) After 60 minutes, D) After 90 minutes based on the given fragments. Generally, different airlines have their own policies regarding when to offer complimentary services during a delay.