A “peccadillo “ is a relatively minor fault or sin, that can be forgiven, hence Option B is the most suitable substitute for the given statement.
Option A is incorrect because “mishap” an unlucky accident or mishappening, hence it is incorrect .
Option C is incorrect because “negligible” means something that’s very small and insignificant that it can be ignored, hence a peccadillo could be negligible.
Option D is incorrect because “lapse” means a temporary failure of memory, judgement or concentration, hence it is not that same as an insignificant fault, hence incorrect .