3. A 4.0 g sample of iron was heated from 0°C to 20.°C. It absorbed 35.2 J of energy as heat. What is the specific
 heat of this piece of iron?
 a. 2816 J/(g•°C)
 c. 2.27 J/g
 b. 2.27 J/(g°C)
 d. 0.44 J/(g.°C)
 i know that the answer is D. but I need an explanation please ! :)