The phenomenon where hair stands on end due to strong emotions like fear, excitement, or awe is called horrification.
Option (A) "tension" refers to mental strain or stress, not a physical reaction of hair standing erect.
Option (C) "terror" means extreme fear, which may cause horrification but is not the specific term for the hair-standing reaction.
Option (D) "horror" refers to intense fear or disgust, again being the cause rather than the physiological effect.
"Horrification" precisely captures the physical response described, making it the most accurate choice.