ANS:C - Platinum-platinum rhodium

The thermocouple that may be used for measuring temperature up to 1873°C (or 1873 Kelvin, as the same temperature value is provided in both degrees Celsius and Kelvin) is platinum-platinum rhodium. Platinum-platinum rhodium thermocouples, also known as type S thermocouples, are commonly used for high-temperature measurements up to around 1600°C to 1700°C. However, they can also be used for temperatures up to 1873°C. These thermocouples offer good stability, accuracy, and reliability at high temperatures, making them suitable for various industrial and laboratory applications where high-temperature measurement is required. Therefore, the correct option for measuring temperature up to 1873°C is platinum-platinum rhodium.