A Lab Assistant Drops a 400

A lab assistant drops a 400.0-g piece of metal at 100.0°C into a 100.0-g aluminum cup containing 500.0 g of water at
In a few minutes,she measures the final temperature of the system to be 40.0°C.What is the specific heat of the 400.0-g piece of metal,assuming that no significant heat is exchanged with the surroundings? The specific heat of this aluminum is 900.0 J/kg ∙ K and that of water is 4186 J/kg ∙ K.

A) 1900 J/kg ∙ K
B) 2270 J/kg ∙ K
C) 3300 J/kg ∙ K
D) 3800 J/kg ∙ K
E) 4280 J/kg ∙ K