Please show work, I believe it to be C.

Ruth Gehrig has received contract offers from three professional aquatic badminton teams. The details are below. Which contract is most valuable? a. Salary of $500,000 per year for 7 years, starting next year. b. Salary of $333,333 per year for 7 years, starting next year, plus a $1 million signing bonus, received immediately $350,000 per year for 3 years, starting next year. In years 4-7, the salary increases to $700,000 per year c. The interest rate is 2% per year