Which of the following could replace ‘imagining’ as used in line 4?

Directions: Read the following passage carefully and answer the given question.

1. Panic hovered on the fringes of my brain.
2. I could barely see anything as it was pitch dark.
3. At times the hazy impression of the moon could be seen
4. or was I imagining things?
5. I was flailing my arms and legs in an attempt to warm up,
6. my eyes desperately scanning the lake. After a while I could
7. make out vague tree shapes on the lake’s edge. A few minutes ago,
8. life was smooth sail, as mundane as any other night.
9. I was shivering under layers of cloth but Mino seemed unaffected.