Explanation:

The Kelvin temperature of a system can be measured using a constant-volume gas thermometer.

Constant-volume gas thermometer:
A constant-volume gas thermometer is a type of thermometer that measures temperature based on the relationship between the pressure and volume of a gas. It relies on the principle that the pressure of a gas is directly proportional to its temperature, given that the volume is held constant.

Working principle:
1. The constant-volume gas thermometer consists of a bulb containing a fixed amount of gas, usually an inert gas such as helium or nitrogen.
2. The bulb is connected to a manometer, which is a device used to measure pressure. The manometer consists of a U-shaped tube partially filled with a liquid, such as mercury.
3. When the bulb is exposed to the temperature being measured, the gas inside the bulb expands or contracts, causing a change in pressure.
4. This change in pressure is measured using the manometer. The difference in the levels of the liquid in the two arms of the U-shaped tube indicates the pressure change.
5. The pressure change is then used to calculate the temperature using the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in Kelvin.
6. By measuring the pressure change and knowing the volume of gas in the bulb, the temperature can be determined.

Advantages of constant-volume gas thermometer:
1. It provides accurate and precise measurements of temperature.
2. It can be used over a wide range of temperatures.
3. It can measure both high and low temperatures.
4. It does not require calibration as it is based on fundamental physical principles.

Other options:
a) Mercury-in-glass thermometer: This type of thermometer is based on the expansion of mercury with temperature. It is commonly used for measuring temperature in everyday applications, but it is not suitable for precise or scientific measurements.
b) Thermocouple: A thermocouple is a device that measures temperature using the voltage produced by the junction of two dissimilar metals. It is commonly used in industrial applications but may not provide the same level of accuracy as a constant-volume gas thermometer.
d) Resistance thermometer: A resistance thermometer, also known as a resistance temperature detector (RTD), measures temperature based on the change in electrical resistance of a metal wire with temperature. It is commonly used in industrial applications but may not provide the same level of accuracy as a constant-volume gas thermometer.

Therefore, the correct answer is option 'C' - constant-volume gas thermometer, which is specifically designed to measure temperature accurately and precisely.