如图所示,过C作CH⊥AB于H,D是Rt△ABC斜边AB上一点,且BD=BC=AC=1,∴CH= 2 2 ,∴S△BDC= 1 2 BD?CH= 1 2 ×1× 2 = 2 2 ,又∵S△BCD=S△BPC+S△BPD= 1 2 BD?PE+ 1 2 BC?PF= 1 2 ×1×PE+ 1 2 ×1×PF,∴PE+PF= 2 2 .故答案选A.