An investment of 12,000 is to be used to make payments of X at the end of the first year, X+50 at the end of the second year, X+100 at the end of the third year, etc. for a total of 30 payments. The fund earns an effective rate of interest of 4%. Calculate X.

A. 63 B. 83 C. 93 D. 113 E. 133