$,$ a manufacturer of lawn$$ mowers, predicts that it will purchase spark plugs next year. estimates that spark plugs will be required each month. A supplier quotes a price of per spark plug. The supplier also offers a special discount$$ option: If all spark plugs are purchased at the start of the$$ year, a discount of $\%$ off the price will be given. can invest its cash at $\%$ per year. It costs to place each purchase order.

Required

$1.$

What is the opportunity cost of interest forgone from purchasing all units at the start of the year instead of in $12$ monthly purchases of units per$$ order?

$2.$

Would this opportunity cost be recorded in the accounting$$ system? Why?

$3.$

Should purchase units at the start of the year or units each$$ month? Show your calculations.