Please choose the correct answer to the question: A 10 g sample of aluminum and a 10 g sample of iron were each heated by 100 joules of energy. The temperature of the aluminum sample rose 11°C, while the temperature of the iron sample increased 23°C. Which statement best accounts for these results?

Answer1: Iron is twice as dense as aluminum. Answer2: Atoms of aluminum are smaller than atoms of iron. Answer3: Using equal masses results in similar heat capacities. Answer4: The specific heat of iron is less than that of aluminum.

Answer format: answer1/answer2/answer3/answer4
Answer: answer4