Final answer:
The prominent physiographic features that appear at the convergent boundary between the Nazca and South American Plates are mountains, specifically the Andes Mountains. Therefore, the correct option is b. Mountains
Step-by-step explanation:
The prominent physiographic features that appear at the convergent boundary between the Nazca and South American Plates are mountains. These mountains are known as the Andes Mountains and are one of the longest mountain ranges in the world. They were formed by the subduction of the Nazca Plate beneath the South American Plate.