Fill in the blank given below using the correct idiom. Sarah decided to _______________ and not confront her colleague about the mistake he made to avoid unnecessary conflict.

The idiom "let sleeping dogs lie" means to avoid bringing up a past issue or stirring up trouble that has already settled. (A) open the floodgates: To allow a large quantity of something to be released or to happen. (B) let sleeping dogs lie: Avoid bringing up a past issue or stirring up trouble that has already settled. (C) take the plunge: To make a bold decision or take a risky step. (D) stand in good stead: To be beneficial or advantageous in the future. (E) wave a dead chicken: To resort to desperate measures.