Answer:
A. Light-years
D. All of the above
Step-by-step explanation:
A. Light-years
As the the distance between stars is very large when denoted as kilometers or miles it is generally written in Light-years i.e. distance covered by light in a year.
D. All of the above
The mass of stars are measured in solar masses i.e., how many times the mass of the star is when compared to our sun.
The brightness of stars is measured in absolute magnitude, apparent magnitude.
Size is also measured in solar radius i.e., how many times the radius of the star is when compared to our sun.
D. Graphs a sample of stars according to surface temperature an absolute brightness
Left side of the diagram is gives the luminosity the right side gives the Absolute magnitude, the top gives the Spectral classification or effective temperatures and the bottom gives the color.
B. Parallax
Parallax is caused due to the change in the observers position to the object being observed.