In order to enter the Mediterranean Sea from the Atlantic Ocean, a ship must pass through:

The correct choice is the Strait of Gibraltar, as it serves as the narrow passageway connecting the Atlantic Ocean to the Mediterranean Sea. This strait is located between the southern coast of Spain and the northern coast of Morocco, and it plays a crucial role for maritime navigation in and out of the Mediterranean region. Ships traveling from the Atlantic must navigate through this strait in order to access the waters of the Mediterranean, making it the essential route for maritime traffic.

In contrast, the other straits mentioned are located in different geographic regions and serve different maritime routes. The Strait of Malacca, for instance, is situated between the Malay Peninsula and the Indonesian island of Sumatra, primarily connecting the Andaman Sea to the South China Sea. The Strait of Georgia is located in British Columbia, Canada, and connects the mainland coastal regions with Vancouver Island, while the Strait of Magellan lies at the southern tip of South America, serving as a passage between the Atlantic and Pacific Oceans. None of these straits connect the Atlantic Ocean directly to the Mediterranean Sea.