Concept:The phrase "hair stood on end" is an idiom that means extreme fear or fright.
Solution:When a person is very afraid, the body may react physically, such as hair rising on end.
Hearing gun-shots is a sudden and terrifying sound for anyone, especially for an old woman.
Thus, the expression shows that she was scared, not crying, inactive, or merely worried.
So the correct meaning is "was frightened."
Answer:Option C (was frightened)