This is a hyperbole bc it is an exaggerration
A. Oxymoron, an oxymoron is when contradictory terms appear in conjunction, with this example a secret isn't suppose to be well known by others but putting the word open in front of it contradicts what a secret really is
I would go with the last one, the way its described seems scary and uninviting. and for instance maybe if you were somewhere that you enjoyed or wanted to be the bug would bother you, but in this case they don't seem like an main concern.
