Answer:
c. Optimum replacement interval (ORI)
Explanation:
Optimum replacement interval used to estimate the most cost effective time to replace an asset on the basis of their replacement cost.
There needs to be a balance between the replacement cost and the value that is being lost by changing the asset.
The useful value must be low to justify replacement cost.
For example if the cost of maintaining a machine has increased a lot as a result of wear and tear, it will be more cost effective to make a replacement in order to minimise cost and increase efficiency