The Reason Why Boulder-Sized Moonlets Are Able to Orbit Within

The reason why boulder-sized moonlets are able to orbit within the Roche limit in Saturn's rings without being destroyed is that:

A) billions of years of alternate freezing and thawing as they pass from sunlight into Saturn's shadow and out again has given them an iron-hard crust of ice.
B) the gravitational forces between the different parts of the moonlet are greater than the tidal forces pulling them apart.
C) they are too small for tidal forces to operate on them effectively.
D) the chemical bonds between their atoms and molecules are greater than the tidal forces pulling them apart.