24. Why is the graphite furnace AA technique more sensitive than the flame AA technique formost of the transition metals? (1) the sample amount is larger for furnace AA； (2) theaverage residence time of atoms in furnace is much longer than in the open flame； (3) thesteady-state concentration of atoms in the flame is much lower than in the furnace； (4) theflame temperature is higher than furnace's； (5) the detector of furnace AA is moresensitive. Your answer:
(A)2,3,5
(B)2,3
(C)4,5
(D)1,4,5
(E)3,4