下列( )项是在D={(z,y)|x(来学网)+y≤1,x≥0,3,≥0}上的连续函数f(x,y),且f
  • A.
    (来学网)f(x,y)=3(x+y)+32xy
  • B.
    (来学网)f(x,y)=3(x+y)-32xy
  • C.
    (来学网)f(x,y)=3(x+y)-16xy
  • D.
    (来学网)f(x,y)=3(x+y)+16xy