Forgetting about the money that's irretrievably gone and instead focusing on the marginal costs and benefits of future options, is the lesson of which of the following?

The ERT Company sells lead pencils in a perfectly competitive market for $5 per box of a dozen pencils. The firm currently produces 2,500 boxes of lead pencils each week and average total cost at this level of production is $5.15

What level of profit is this firm earning? Explain.

Decreases in autonomous spending cause rightward shifts of the aggregate demand and supply curves

Indicate whether the statement is true or false