A coffee-cup calorimeter (heat capacity 320 J °C⁻¹) contains 100.0 g of water at 24.0 °C. Nickel has a specific heat capacity of 0.444 J g⁻¹ °C⁻¹. What mass of nickel at 260 °C must be added so that the final temperature of the system is 29.5 °C?
a) 57g
b) 40g
c) 23g
d) 92g