Here's why:
* A When we stopped by garden: This lacks a complete thought. It's missing a verb to explain what happened when they stopped.
* B Stop: This is a single word and doesn't express a complete thought.
* C We she: This is grammatically incorrect and doesn't make sense.
* D Stopping saw: This also lacks a subject and is incomplete.
To make "When we stopped by garden" a complete sentence, you need to add a verb. For example: "When we stopped by the garden, we saw a beautiful rose bush."