Answer:
A.
Explanation:
Im just guessing because it sounds like it describes a hypothesis the most and you said its urgent
Answer
The apparent brightness by inverse square law is 
Explanation:
b = L / ( 4 pi d^2 )
b = apparent brightness of the star (in watts/meter2)
L = luminosity of the star (in watts)
d = distance to the star (in meter)
pi = approximately 3.14159265

put all values in formula


Answer:
The corona is hotter than the photosphere,
Explanation:
We can calculate it by applying Newton's version of Kepler's third law with Earth's orbital period (1 year) and Earth's average distance from the Sun (1 AU).