Greg Begins Contributing to His Retirement Plan by Making $300

Greg begins contributing to his retirement plan by making $300 per month at the start of each month for 4 years. Afterwards, he increases his payments to $500 per month for the last year. If the rate of interest throughout this time is 6% compounded semi-annually, determine how much Greg will have in his retirement at the fifth year.

A) $22,973.07
B) $23,073.07
C) $23,473.07
D) $24,404.18
E) $24,890.28