Foreshadowing in a Narrative Excerpt

Read the following excerpt from a fictional story:

As the old man sat on the bench, he stared at the children playing in the park. A faint smile crossed his lips, but his eyes betrayed a sadness that lingered in his thoughts. He glanced at the large oak tree, its branches swaying gently in the breeze, and whispered to himself, 'Not many years left now. I hope they find their way.'

Based on this excerpt, which option best illustrates the use of foreshadowing?