Rola Quit Her Job as a Buyer for Center Point

Rola quit her job as a buyer for Center Point to start her own hair dressing salon, Goldilocks. She gave up a salary of US$40,000 per year, invested her savings of US$30,000 (which was earning 5 percent interest) and borrowed US$10,000 from a close friend, agreeing to pay 5 percent interest per year. In her first year, Rola spent US$18,000 to rent a salon, hired a part -time assistant for US$12,000 and incurred another US$15,000 on equipment and hairdressing material. Based on this information, what is the amount of her explicit costs?

A) US$45,500
B) US$87,000
C) US$47,000
D) US$45,000