If the distance between us and a star is doubled, with everything else remaining the same, the luminosity
A) is decreased by a factor of four, and the apparent brightness is decreased by a factor of four.
B) is decreased by a factor of two, and the apparent brightness is decreased by a factor of two.
C) remains the same, but the apparent brightness is decreased by a factor of two.
D) remains the same, but the apparent brightness is decreased by a factor of four.
E) is decreased by a factor of four, but the apparent brightness remains the same.
Answer: d