Answer:
a) Measuring heat of combustion
Explanation:
Calorimeter -
It is an instrument which is used for the measurement of the heat for various physical changes or chemical reaction .
The amount of heat released or absorbed can be measured by using calorimeter .
The device is commonly used for the study of chemistry , thermodynamics , etc.
Hence , the proper use of a calorimeter is ( a ) .
Answer:
(a) heat of combustion
Explanation:
A Calorimeter basically is used for measuring heat of combustion. commercially it is referred to as a bomb calorimeter.
Temperature is measured ny an instrument called thermometer.
The amount of oxygen consumed in a combustion process is determined by  stoichiometric calculations.
Entropy can not really be measured using an instrument, but can be determined from the heat of a reaction and temperature
