Connotation refers to the emotions words can evoke. Words can have either a positive or a negative connotation.
Words evoking fear in the audience are likely to have a negative connotation since fear is a negative feeling. Therefore, for the writer to make the reader feel fear, they should be very specific with their word choice; particularly with adjectives they decide to use since this word category is the one that best describes emotions or actions. From the examples in question, I believe that B is your answer.
In this sentence, a simile has been used (like an icicle) so you can really understand how Aiden's body froze, you can make a mental image of it. His heart not only beat rapidly, but it "pounded" which means that it striked or hit heavily and repeatedly. Aiden did not look over the railing but he "peered over" it entailing that he looked carefully or with difficulty (that verb has two meaning components with a negative connotation)