It means to "stay in a place longer than necessary, typically because of a reluctance to leave"
or
"spend a long time over (something), be slow to disappear or die"
B. is where you write
it says "fustian WRITING is where you WRITE pompous, bombastic nonsense." write/ writing does not have to be repeated. also it's unnecessary. and if you took out fustian writing there would be no subject of the sentence.
In eighteenth-century English courts, defendants has to appear at their trials wearing C. Manacles.