What is the sum of the described series? Use S_n=n(a₁+aₙ₂). A company has agreed to make a yearly monetary gift to a charity. The first year it donates $2,000. Each year after, it promises to increase the donation by $500. How much total money will the company have given to the charity after 15 years?
A. $82,500
B. $77,000
C. $9,000
D. $5,500