There's a bunch of popular hats around the world so it depends :D
First of all, you dont have the answers.
But the answer is "Companies replaced hand-operated brakes with air brakes on trains" is the best answer because this stopped many of the fatalities that were caused by brake failures." which is I say on what you are using D
A. Major Ethnic Groups of North Africa
This is an example of face-saving behavior.
She did this in order to avoid feeling embarrassed, or to lessen the embarrassing situation which may have happened if she showed that she heard them fighting. By pretending she didn't hear anything, she kept the appearance of a normal situation.