The luminosity $L$ of a star is represented by $L = 4\pi r^2 \sigma T^4$ in which $r$ denotes the star’s radius, $T$ denotes the star’s temperature and $\sigma$ is a constant with units $\text{W m}^{-2}\text{ K}^{-4}$. What are the SI base units of $L$?
- A$\text{kg m}^2\text{ s}^{-1}$
- B$\text{kg m}^2\text{ s}^{-2}$
- C$\text{kg m}^2\text{ s}^{-3}$
- D$\text{kg m}^2\text{ s}^{-4}$