D. horrors
Horrors is the best choice because of the word "scorpions". While all of the options fit, it is important to think about Shakespeare's choice for scorpions versus flies, black cats, or ghosts. Scorpions carry a frightful connotation. Finding one resting on your pillow at night would be horrific. Thoughts can be either good or bad - not a good choice. Superstitions do not carry the same fear either. Doubts are also not strong enough for a scorpion's image. Therefore, horrors would be the best answer.