Excerpt from: Battling Cancer: One Woman's Journey
Tracy Wilson

As she opened the box, the rusty hinge made a screech much like someone scraping fingernails across a blackboard. The news Julianne received in a postcard that day was much more unnerving.

Which definition of the word unnerving BEST fits the context of this sentence from the article?
A) causing a person to feel encouraged
B) causing great anxiety and moments of rage
C) making a person to be thoughtful and meditative
D) making a person upset or to feel empty of courage