Mr Johnston Has Been Investing $5,000 into His Savings Plan

Mr. Johnston has been investing $5,000 into his savings plan at the end of every year for the last 17 years. His investments have earned 10.6% compounded semi-annually. If he increases his annual contributions to $6,000, how much longer will it take for his savings plan to reach $1,000,000?

A) 9 years
B) 11 years
C) 13 years
D) 15 years
E) 17 years