Answer:
A large batch
Explanation:
Batch processing is used by large businesses to automate production process in such a way that efficiency is achieved in the shortest time.
This requires processing of a set of products as opposed to individual transactions.
In the given scenario where a process step has a large setup time and a small pure-processing time per unit, it means that the time to set up the production process is much while the individual processing time per product is small.
A large batch will be best in this situation because once it is set up more product will be processed at once.
However if smaller batch was used the setup time will reoccur often and slow down the process.
