Answer : 4. "काठमांडू"
Explanation :

The South Asian Association for Regional Cooperation (SAARC) is an organization comprising eight South Asian nations, namely Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka. The headquarters of SAARC is situated in Kathmandu, the capital city of Nepal. SAARC aims to promote regional cooperation and development among its member countries in various areas, including economic, social, cultural, and environmental aspects.