$[$Study guide $-$ final exam$]$ A firm practices a pure chase strategy. Production last quarter was $1000.$ Demand over the next four quarters is estimated to be $900,700,1000,$ and $1000.$ Hiring cost is $$20$ per unit, and layoff cost is $$5$ per unit. Over the next year, what will be the sum of hiring and layoff costs?

iswered

$$2,500$

$$7,500$

$$12,500$

$$500$

$$7,000$