Which of the following are period costs? Select one: a. workers wages in the plant maintenance department O b. workers wages on an assembly line O c. workers wages in the shipping department O d. factory workers wages paid for statutory holidays Gift Gallery sold 2,000 Zooglars during 2020. Information is provided concerning the Zooglar product: Sales............... $ 60,000 Variable costs.. 24,000 Fixed costs.. 10,000 Net income. $ 26,000 If Gift Gallery sells 30 more units, by how much will its profit increase? Select one: 0 a $900 O b. $18 O c. $390 od. $540