Why is the optical density of pure water and water with pepsin, BAPNA, and buffer (but not incubated) both 0?

A) pepsin, BAPNA, and buffer all dissolve as colorless at any concentration.

B) pepsin, BAPNA, and buffer are all colorless at this concentration.

C) The optical density of BAPNA counteracts the optical density of pepsin and buffer, making the total zero.

D) The spectrophotometer cannot make any readings of blue solutions.