The correct answer is D. Singapore.
The Shangri-La Dialogue is an annual security forum held in Singapore. It is hosted by the International Institute for Strategic Studies (IISS) and was first held in 2002. The forum brings together defense and security officials, policymakers, academics, and business leaders from around the world to discuss regional and global security issues.
The 14th Asia Security Summit was held from 30 May to 1 June 2015. The theme of the summit was “Shaping the Security Architecture of the Asia-Pacific Region: Towards a New Regional Order.” The keynote speaker was US Secretary of State John Kerry.
The other options are incorrect. Beijing is the capital of China. Bangkok is the capital of Thailand. Jakarta is the capital of Indonesia.