Everyone was listening to the news of earthquake with mounting anxiety.

Answer: Option C

Interest : the feeling of wanting to know or learn about something or someone.
Eagerness : enthusiasm to do or to have something; keenness.
Uneasiness : a feeling of anxiety or discomfort.
Grief : intense sorrow, especially caused by someone's death.
Anxiety : a feeling of worry, nervousness, or unease about something with an uncertain outcome.

Synonym of Anxiety is Uneasiness