A 0.20 kg sample is warmed with a 150 W heater for 30 s, and its temperature rises by 25 °C. Given the following specific heats:
• Aluminum: 900 J kg⁻¹ °C⁻¹
• Copper: 385 J kg⁻¹ °C⁻¹
• Brass: 380 J kg⁻¹ °C⁻¹
• Lead: 130 J kg⁻¹ °C⁻¹
Identify the material that most closely matches the sample.