The difference of temperature in a material can convert heat energy into electrical energy. To harvest the heat energy, the material should have

• A

  high thermal conductivity and high electrical conductivity
• B

  low thermal conductivity and low electrical conductivity
• C

  high thermal conductivity and low electrical conductivity
• Correct answer
  D

  low thermal conductivity and high electrical conductivity

Hence, the correct answer is option: 'D'.