Answer:
D) idle time is acceptable if there is no work to do
Step-by-step explanation:
A bottleneck happens when a production process is saturated with inflows from work in progress units from previous processes. The process cannot handle them all and process them so queues start to form. Bottlenecks slow down total production, reducing efficiency and productivity.
Idle time is defined as time spent waiting, i.e. some production process will be halted until enough WIP units arrive.