Andie is considering leaving her job as an attorney to pursue her passion by starting a dog-grooming business. She currently takes home $6000 per month from her job. She pays $2000 per month to rent her house. If she were to start the dog-grooming business, she would operate it out of the currently-unused room at the back of her house and she would work at it full-time. She would hire additional workers and pay them a total of $3000 per month, while spending $1000 per month on materials. She already has everything else she needs to start the business. What are the monthly economic costs of Andie's potential dog-grooming business?

a. $9,000

b. $12,000

c. $10,000

d. $6,000

e. $8,000