Which sentence is most clearly written?

The choice is most effectively structured because it starts with the context of the officer's arrival, setting the scene before introducing the key information about probable cause. This chronological order enhances clarity since it helps the reader understand the sequence of events as they unfold.

Beginning the sentence with the action of arriving at the scene establishes the situational context, which is essential for understanding why the officer had probable cause. This arrangement allows the reader to follow the logic and flow of the information more naturally. By placing the officer's action first, it creates a more engaging narrative that draws the reader in and sets a clear framework for the reasoning behind the arrest.

In contrast, the other option presents the probable cause first, which could lead to confusion regarding the timing of events and the relationship between the officer's arrival and the arrest decision. Thus, clarity is enhanced in the preferred choice, making it the clearer option for effective communication.