Jenny would like to plan for her son's college education. She would like her son, who was born today, to attend a private university for 4 years beginning at age 18. Tuition (paid beginning each year) is currently $15,000 a year and has increased at an annual rate of 8% per year. Jenny can earn an after- tax rate of return of 12%. How much must Jenny save at the end of each year if she would like to make her last payment at the beginning of her son's first year of college?

a. $4,058.86

b. $3,657.54

c. $3,930.15

d. $4,075.71