U={(x,y)|x∈R,y∈R},A={(x,y)|2x-y+a＞0},B={(x,y)|x+2y-b≤0},则点P(

U={(x,y)|x∈R,y∈R},A={(x,y)|2x-y+a＞0},B={(x,y)|x+2y-b≤0},则点P(1,4)∈A∩(CuB)的充要条件是.( )
A.a＞2,b＞9 B.a＜2,b＞9 C.a＞2,b＜9 D.a＜2,b＜9