When Comparing the Line Representing Bacterial Growth at 6°C to the Line

When comparing the line representing bacterial growth at 6°C to the line representing growth of organisms at 4°C,which of the following is true?

A) More growth occurs at 4°C.
B) The rate of growth is lower at 6°C.
C) There were preexisting contaminants in both cases.
D) On day 10 the population at 4°C was half of the population at 6°C.