The correct answer is the Tuamotu Archipelago.
If Magellan’s course had taken him a little farther north or south shortly after crossing the Tropics of Capricorn, he might been able to restock food and water supplies in the Tuamotu Archipelago.
The Tuamotu Archipelago is also known as Paumotu and is part of French Polynesia in central South Pacific Ocean. It has ring-shaped coral reef best known as an atoll, which includes many coral reefs. Indeed it is considered the largest portion of coral atolls on Earth. The largest one receives the name of Rangiroa.
tan A should be the corner try work out work out:

first and then add all the others (B=90)
Explanation:
A and C should be the same
Scenario C: Electrolytes.