What is the S.I unit of temperature?

1. Kelvin
2. Centigrade
3. Fahrenheit
4. None of these

The SI (Système International) base unit for thermodynamic temperature is the kelvin (K). It is the standard unit used in the scientific community worldwide. While Celsius (°C, formerly Centigrade) and Fahrenheit (°F) are commonly used scales, they are not the fundamental SI unit. The Kelvin scale starts at absolute zero.