单项选择题

According to the passage, in the Cepheid variable method all of the following have a significant role in the calculation of the distance of a galaxy EXCEPT

(A) The intrinsic luminosity of a Cepheid
(B) The comparative luminosity of ordinary stars
(C) The observed brightness of the Cepheid
(D) The data suggesting the expansion of the universe
(E) The correction of the period-luminosity relation for the star being observed