The plant manager at a local automotive manufacturer plans to make sure the current capacity utilization for the plant does not exceed $88\%$ of the maximum plant capacity. The reason the plant manager implemented this capacity cushion is$?$

Some of the manufacturing personnel may be sick and therefore may take a sick day during the next several months

The raw materials are being purchased from a new supplier, so they may not run through the automated machinery consistently

Several pieces of equipment are old and cannot be counted on to run at full speed

Only a$.$ an b$.$ are correct

All of the above