What was the first nuclear submarine?

• A. USS Nautilus (SSN-571)
• B. USS Los Angeles (SSN-688)
• C. USS Ohio
• D. USS Jimmy Carter (SSN-23)

Answer: (A)

The main idea is recognizing the historical milestone of nuclear propulsion in submarines. The first submarine powered by a nuclear reactor demonstrated that a boat could operate underwater for extended periods without surfacing, vastly increasing stealth and range. That landmark vessel is the USS Nautilus, which proved the concept and kicked off the nuclear-submarine era. The other ships listed came later: Los Angeles-class submarines were introduced decades after Nautilus as modern attack boats, Ohio represents a later ballistic-missile submarine, and Jimmy Carter is a Seawolf-class attack submarine from the 1980s. Nautilus is the correct answer because it began the nuclear-propulsion era that all subsequent designs built upon.