Explanation:

- The passage describes an incident during a walk, where Shiela notices something on her shoe. The word needed should logically outline her perception or discovery of the object.

- Option 1: "thought" implies guessing or forming an idea, which doesn't indicate physical awareness of the shoe situation.

- Option 2: "felt" suggests a tangible sensation, as if she physically sensed the object's presence, which doesn’t align perfectly with the described scene of recognition or awareness beyond a physical sensation.

- Option 3: "found" indicates the act of discovering or noticing the object directly, completing the idea effectively.

- Option 4: "had" implies possession, not a process of awareness or discovery.

The most contextually suitable option to fill in blank 3 is:

- Option 3: found