To What Does the Phrase "Jeans Length" Refer

To what does the phrase "Jeans length" refer?

A) the maximum distance over which a temperature fluctuation can occur in a "connected" universe
B) the minimum diameter of a density fluctuation that can collapse gravitationally to form a galaxy or other astronomical object
C) the minimum distance over which a temperature fluctuation can occur in a "connected" universe
D) the maximum diameter of a density fluctuation that can collapse gravitationally to form a galaxy or other astronomical object