Identifying Foreshadowing in Literary Excerpt

In literature, foreshadowing is a narrative device used by authors to hint at events that will occur later in the story. Consider the following excerpt from a fictional novel:

"As Sarah walked through the old, creaky house, she could not shake the feeling that someone was watching her. The shadows danced oddly along the walls, and the wind howled fervently outside, rattling the windows. A single flickering candle illuminated the room, casting eerie shapes that made her heart race."

Based on this excerpt, which line provides an example of foreshadowing?