What kenwood amp would be right for 1 kfc w3012 kenwood sub. The amps are the kac 8105d or the 7205. Thanks?

The subwoofer has 400 watts rms and 1200 max power, the 8105d mono amp has 500 watts rms and 1000 max power, the 7205 amp is 500 watts rms and 1000 max power and it has a cooling fan. if you wan't more specs on this visit www.kenwood.ca. I dont care what th price is but i just need someone to tell me which is better for the sub because i am a beginer with this stuff. Thanks a lot guys.