Which of These Equations Represents the Dependence of the Total $\sigma$

Multiple Choice

Which of these equations represents the dependence of the total energy flux F of radiation emitted per unit area by a blackbody (e.g., star) on its temperature T with $\sigma$ a constant?

A) FT⁴ = $\sigma$
B) F⁴ = $\sigma$ T
C) F = $\sigma$ /T
D) F = $\sigma$ T⁴