Final answer:
The deepest parts of the Pacific Basin are located near the margins of South America, Japan, and the Marianas Islands, where subduction of tectonic plates occurs.
Step-by-step explanation:
The deepest parts of the Pacific Basin are located (b) near the margins of South America, Japan, and the Marianas Islands.
The Pacific Basin is known for its deep trenches, such as the Mariana Trench, which is the deepest part of the ocean. These trenches are formed due to the subduction of tectonic plates. The Pacific Plate subducts beneath the plates of South America and Japan, creating these deep ocean trenches.