The correct option is
B Quarrel
To fall out means to have an argument.
“Quarrel” means a heated argument or disagreement.
“Fail” means to not give an successful attempt at something.
To “disintegrate” means to break down into pieces
“To disperse” means to split or leave a common point at once
“To scatter” means to throw in random various directions.
Hence option A is the correct meaning of the given phrase