The correct answer is:
Passini varies his syntax and structure.
In Ernest Hemingway´s A Farewell to Arms, Lieutenant Henry and other ambulance drivers argue about the war. The driver named Passini is the most philosophically opposed to it. The narrator´s use of simple sentences suggests he´s practical and modest and reflects his lack of passion for the war even though he accepts it as the only option.
On the other hand, Passini´s variation on his syntax and structure shows an opposite position and personality.