The Indus Valley Civilization is one of the world's oldest civilizations, and it existed in parts of present-day India and Pakistan.
- Mohenjodaro and Harappa are major Indus Valley sites, but they are located in present-day Pakistan, not India.
- Lothal is an important site of the Indus Valley Civilization located in Gujarat, India, and is famous for its dockyard and maritime activities.
- Ahar is a different archaeological site, unrelated to the Indus Valley Civilization.
Final Answer:
\[
\boxed{\text{The correct answer is (3) Lothal.}}
\]