For an application the change in enthalpy of carbon dioxide from 30 to 1500C at 100 kPa

Question:

For an application the change in enthalpy of carbon dioxide from 30 to 1500°C at 100 kPa is needed. Consider the following methods and indicate the most accurate one.
a. Constant specific heat, value from Table A.5.
b. Constant specific heat, value at average temperature from the equation in Table A.6.
c. Variable specific heat, integrating the equation in Table A.6.
d. Enthalpy from ideal gas tables in Table A.8.