The correct answer is option 3, Bab-al-Mandeb. Bab-al-Mandeb is a strait that separates Asia from Africa. It is located at the southern end of the Red Sea, connecting the Gulf of Aden to the Red Sea. The strait is strategically important as it controls the access to the Suez Canal, which is a major shipping route between Asia and Europe. Option 1, Malacca, is a strait located between the Malay Peninsula and the Indonesian island of Sumatra. Option 2, Hormuz, is the Strait of Hormuz, which separates the Persian Gulf from the Gulf of Oman. Option 4, Bosphorus, is a strait that connects the Black Sea to the Sea of Marmara, separating Europe and Asia within Turkey.