I think it is the third one but im not 100% sure
It is a figure of speech. Obviously they hadn't actually been on the verge of cutting each other's throats, it's a fancy way of saying they were all very angry and couldn't stand each other. The author's purpose was to imply that before something happened, they were very angry and unable to stand each other.
The first reason is because woman have a lot of emotions that can lead to anger. When boys get mad they fight each other.
The second reason is because sometimes when boy and girls have best friends , something can happen between both of them. For example, when your best friend talks behind you back you start arguing which can lead to violence.
A. Pathos
pathos is the power of performance and description. it's usually used to produce feelings if sadness and sympathy. It was used in this context on what does the admiration of we all being of English descent results in which is 'Nothing'
