Final answer:
The 4th Fleet is responsible for naval operations in the Eastern Pacific Ocean and Caribbean Sea.
Step-by-step explanation:
The area of responsibility for the 4th Fleet is b) Eastern Pacific Ocean and Caribbean Sea. This fleet oversees naval operations in this region, including various territories and nations bordering the Eastern Pacific and the islands of the Caribbean Sea. The 4th Fleet's responsibility does not extend to the Atlantic Ocean towards North America, South America, or Western African coasts, nor to the Western Pacific involving nations from Eastern and Southeastern Asia or the Central and Southern parts of Asia. The fleet also does not cover the Mediterranean Sea, Black Sea, Indian Ocean, Arabian Gulf, or the areas of Oceania, which includes Australia, New Zealand, and neighboring Pacific islands.