You arrive at the airport and wonder to what extent the security checkpoint is a lean operation. Among other things, you observe that it takes about 30 seconds to check an ID, scan a passenger for weapons, and X-ray their luggage. However, the average cus- tomer spends about 20 minutes in the process. This observation is an example of which of the following?
a. Waste of capacity
b. Waste of a flow unit’s time
c. Waste of materials
d. This observation is unrelated to lean.