Sally Has Invested a Constant Amount at the End of Every

Sally has invested a constant amount at the end of every six months for the last 40 years. She has made wise investment decisions and has earned a return of 16.4% compounded semi-annually. Today the value of her savings has reached $2,500,000. What amount has she been investing every half-year?

A) $91.66
B) $375.29
C) $5,834.15
D) $61,983.84
E) $205,375.29