19. consider the vector field f = rp(y i - x j), where b e r, r =xi +yj andr = ir| lf absolute value of the line integral f dr along the closed curve c :x + y =

19. Consider the vector field F = rP(y i - x j), where B e R, r =xi +yj andr = Ir| lf absolute value of the line integral F dr along the closed curve C :x + y = a2 counter clockwise) is 27t, then Bis (a)-2 (b)-1 ve edo (Cc) 1 (d) 2