A Red Filter Passes Light at the Long-Wavelength End of the Visible

Multiple Choice

A red filter passes light at the long-wavelength end of the visible spectrum as shown,for example,in Figure 10-4 in Comins,Discovering the Essential Universe,6th ed.Star 1 and star 2 are viewed through identical red filters,and star 1 appears brighter than star 2 through the filter.What can be determined from this information?

A) Star 1 is hotter than star 2.
B) Star 2 is hotter than star 1.
C) Star 1 is more luminous than star 2.
D) Nothing can be concluded from this fact alone.