cost reduction methods

It very much depends on the context of the question. The most likely place this could be asked is in a target costing question when we are looking for ways of reducing the cost down to the target. I give plenty of examples of how we might do this in my free lectures on target costing. I ask you again, have you watched my lectures? The lectures are a complete free course for Paper PM and cover everything needed to be able to pass the exam well.